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INTERPRETATION  OF 
DENTAL  AND  MAXILLARY  ROENTGENOGRAMS 


INTERPRETATION 

OF 

DENTAL  AND  MAXILLAEY 

.     ROENTGENOGRAMS 


BY 

ROBERT  H.  IVY,  M.D.,  D.D.S. 

MAJOR,   MEDICAL  RESERVE   CORPS,   UNITED   STATES  ARMY;    ASSOCIATE   SURGEOX, 

COLUMBIA    HOSPITAL,    MILWAUKEE;    FORMERLY    INSTRUCTOR    IN 

ORAL    SURGERY,    UNIVERSITY    OF    PENNSYLVANIA. 


^V1TII  259  ILLUSTRATIONS 


ST.  LOUIS 
C.  V.  I\[OSBY  COMPANY 

1918 


Copyright,  1918,  By  C.  V.  Mosby  Company 


Press  of 

C.  V.  Mosby  Coinlmiiy 

St.  Louis 


TO  MY  UNCLE 

MATTHEW  H.  CRYER,  M.D.,  D.D.S. 


PREFACE 


Tlie  purpose  of  this  small  volume  is  to  present  to  iiiem- 
bers  of  the  medical  and  dental  professions  the  data  neces- 
sar}^  for  making  an  intelligent  diagnosis  of  pathologic 
conditions  about  the  teeth  and  jaw  bones  in  which  roent- 
gen examination  plays  a  part.  It  is  hoped  that  a  basis 
for  this  will  be  formed  by  study  and  comparison  of  the 
numerous  normal  and  al^normal  views  sho^^^l. 

It  has  been  said  that  the  actual  making  of  the  roent- 
genogram is  the  elementary  feature  of  roentgenology, 
and  that  those  who  know  how  to  interpret  roentgeno- 
grams are  few  in  number  compared  with  those  who  know 
how  to  make  them.  It  is  to  interpretation  rather  than 
to  technic  that  the  writer  has  endeavored  to  call  par- 
ticular attention  in  the  following  pages,  references  to 
technic  being  limited  to  special  points  involved  in  ex- 
amination of  the  teeth  and  jaw  bones, 

A  departure  from  the  usual  method  of  presentation 
lies  in  the  fact  that  in  this  work  the  roentgenograms  are 
negative  reproductions ;  i.  e.,  they  correspond  with  the 
original  negatives  in  that  bone  and  hard  tissues  are  light, 
and  soft  tissues  and  spaces  are  dark,  instead  of  being 
merely  prints  of  the  negatives,  in  which  the  dark  and 
light  portions  arc  reversed;  so  that  in  studying  these 
illustrations  there  is  a  near  approach  to  natural  condi- 
tions found  in  the  original  negatives. 

In  a  majority  of  the  odontograms  showing  periapical 
pathology,  the  writer  has  been  in  a  position  to  compare 
the  pictures  with  the  conditions  found  at  operation,  so 
that  in  these  cases  the  interpretations  are  not  based 
mer<'ly  upon  surmise. 

The  writer  desires  to  thank  Dr.  j\r.  H.  Cryer  for  per- 

9 


10  PEEPACE 

mission  to  use  the  excellent  anatomic  illustrations  taken 
from  his  Internal  Anatomy  of  the  Face,  and  also  his 
associates,  Drs.  P.  B.  Wright  and  M.  PI.  Mortonson,  for 
cooperation  and  help  in  the  preparation  of  roentgeno- 
grams. 

Acknowledgment  is  also  due  the  publishers  for  their 
patience  in  waiting  for  the  manuscript,  Avhich  was  con- 
siderably delayed  owing  to  the  exigencies  of  military 
service. 

EoBEET  H.  Ivy. 

Milwaukee,  Wis. 


CONTENTS 


PART  I 

PAGE 

CHAPTER  I 
General    Considerations 17 

CHAPTER  II 

Anatomy  of  the    Teeth   and    Jaws,    avit]i    Special   Reference   to 
Roentgenogram  Interpretation 24 

CHAPTER  III 

Pathology  in  Relation  to  Dental  Roentgenology 36 

CHAPTER  IV 

Correlation  of  Clinical  Findings  with  Roentgenographic  Exam- 
ination  49 

CHAPTER  V 

Roentgenographic  Findings  About  the  Teeth  and  Jaavs  in  Their 
Relation  to  Prognosis  and  Treatment 62 

CHAPTER  VI 

Stereoscopic  and  Other  Methods  op  Localization 67 


PART  II 

CHAPTER  VII 
Interpretation 77 


11 


ILLUSTEATIONS 


FIG.  TAGE 

1.  Showing   cancellated    lioue    of    alveolar    process 25 

2.  Anterior  view  of  skull,  showing  anterior  opening  of  nasal  cliamber  2(i 

3.  Showing  thickness  of  bone  between  the  apices  of  the  molar  roots 

and  the  maxillary  sinuses 27 

4.  Showing  smooth  prominence  in  floor  of  maxillary  sinus     ....  27 
.5.  Showing  floor  of  maxillary  sinus   dipping  down  between   roots  of 

molar  tooth 2S 

fi.   Showing  maxillary  sinus  not  extending  much   anterior  to  the   first 

molar 2S 

7.  Maxillary  sinus  extending  in  front  as  far  as  the  region  of  the  first 

premolar  tooth 29 

8.  Showing  anterior  palatine  fossa  just  behind  and  between  tlu>  upper 

central  incisor  teeth 30 

9.  Showing    cancellated    internal   structure   of    mandible    with    mental 

foramen  below  and  between  roots  of  premolar  teeth     ....  31 

10.  Plate  of  right  side  of  face,  with  head  placed  especially  to  show 

molar  region     .     .     ^ 32 

11.  Diagrammatic    illustration    of    Fig.    10 33 

12.  Plate  of  left  side  of  face,  showing  normal  anatomic  landmarks  and 

impacted   upper   third   molar 34 

13.  Diagrammatic  illustration  of  Fig.  12 35 

14.  Inflammatory  periapical  tissue  of  the  more  acute  type 39 

15.  Chronic   type    of   periapical   inflammation 39 

16.  Case   of   long-standing   inflammation 41 

17.  Mass  of  squamous  epithelial  cells .•  ^-'^ 

IS.  Early  stage  of  cyst  formation 43 

19.  High  power  view  of  epithelial  cyst  lining 43 

20.  Later  stage  of  cyst  formation 44 

21.  Faradic  battery  used  to  test  pulp  vitality 50 

22-^.  Diagram  of  teeth  with  faradic  I'oaction,  etc.,  indicated      ....  54 

22-B.  Plate  of  left  side 54 

22-C.  Plate   of   right   side 55 

22-D  and  E.  Films   of   upper  left   teeth 55 

22-i^  and  G.  Films  of  upper  right  teeth 55 

23.  Eisen  plate  rest  attached  to  stand  for  taking  head  plates     .     .     .  5(i 

24.  Position  of  head  and  angle  for  left  side  of  jaws 57 

25.  Position  for  exposing   intraoral    dental    films 58 

26.  Diagram   showing   position    f(M'    ex]iiising   sinus    plate,    ami   projec- 

tion of  the  sinuses  i.n  llie  plate 5i) 

13 


14  ILLUSTRATIOjSTS 

FIG.  PAGE 

27.  Opacity  due  to  empyema  of  left  maxillary  sinus 60 

28.  Position  and  angle  of  tube  for  iirst  expjosure  in  plate  stereogram  cf 

the  jaws 68 

29.  Diagram  giving  the  angles  of  the  tube  in  making  stereograms  of 

the   jaws   and   teeth 68 

.30.  Position  and  angle  of  tube  for  second  exposure  in  plate  stereogram 

of   the   jaws 69 

31.  Stereogram   showing  unerujated  impacted  upper  third  molar  lying 

to  lingual  side  of  arch 71 

32.  Central    position   of    the    tube   prior   to    making   stereoscopic    film 

exposures 73 

33.  Position  of  tube  for  exposure  of  first  film  in  making  dental  stereo- 

gram     73 

34.  Position  of  tube  for  exposure  of  second  film  in  making  stereogram     74 

35.  Method  of  mounting  stereoscopic  films  so  that  they  may  be  adjusted 

to   desired  p)Ositions 75 

36.  Hand  stereoscope 75 

37.  Diagrammatic   illustration   of   localization 76 

38-85.     Eoentgenograms   of   upper   anterior   region     , 79-90 

86-117.  Roentgenograms   of  upper   right   region 91-98 

118-161.  Roentgenograms  of  upper  left  region 99-109 

162-175.  Roentgenograms  of  lower  front  region 110-113 

176-189.  Roentgenograms  of  lower  right  region      .     .     .     .     .     .      113-116 

190-205.  Roentgenograms  of  lower  left  region 117-120 

206-217.  Roentgenograms  illustrating  the  use  of  the  x-ray  as  a 

check  on  root  canal  treatment ,     .      121-125 

218-219.  Roentgenograms  illustrating  the  use  of  the  x-ray  as  a  check 

on  surgical  treatment 126 

220-225.  Views  of  impacted  canines,  no  attempt  at  localization     .     .127 

226-229.  Localization    of    impacted    canine 128-129 

230-237.  Roentgenogram   showing  impacted   molars 130-134 

238.  Roentgenogi'am  of  supposedly  edentulous  patient  81  years  of  age    134 

239.  Large  area  of  bone  destruction  in  left  angle  and  ramus  of  man- 

dible     135 

240.  Roentgenogram  of  same  case  as  Fig.  239  taken  four  months  later  135 

241.  Cyst  of  right  side  of  upper  jaw 136 

242.  Roentgenogram  showing  extensive  bone  destruction  of  lower  jaw 

due   to    acute    osteomyelitis 136 

243.  Large  area  of  bone  destruction  on  right  side  of  mandible     .     .     .    137 

244.  Large  infected  cyst  on  right  side  of  mandible  due  to  infection 

about  roots  of  first  molar 137 

245.  Calcified   composite   odontoma    of    right   side   of   mandible   in    an 

adult 138 

246.  Calcified  composite  odontoma  of  lower  jaw 138 

247.  Calcified  composite  odontoma  iji  a  boy  ten  years  of  age     ....  138 

248.  Periapical  bone  destruction  connected  with  lower  left  second  molai'  139 


ILLUSTEATIOTvTS  15 

>'IG.  PAGE 

24^).  Retained  piece  of  root  of  lower  left  first  molar 139 

250.  Root   of  upper   right   first   molar   lost   in   maxilhiry   sinus   durino- 

attempted  extraction 140 

251.  Root   of   upi^er   right   first   molar   lost   in  maxillary   sinus   during 

attempted  extraction 140 

252.  Roentgenogram  of  right  side,  showing  laclv  of  development  of  teeth  141 

253.  Same  ease  as  in  Fig.  252,  showing  similar  condition  on  left  side     .  141 

254.  Fracture  of  left  side  of  mandible  just  in  front  of  second  molar     .  142 

255.  Fracture  of  left  side  of  ma]idil)le  in  second  premolar  region     .     .  142 

256.  Fracture  of  left  side  of  mandible  near  canine  tooth 143 

257.  Fracture  through  neck  of  mandilile 143 

258.  Double  fracture  of  mandible  in  molar  region  ou  each  side     .     .     .  144 
250.  Same  case  as  in  Fig.  258,  showing  swaged  metal  intermaxillary 

splint  in  position 144 


INTERPRETATION  OF  DENTAL  AND 
MAXILLARY  ROENTGENOGRAMS 


PART  I 


CHAPTER  I 
GENERAL  CONSIDERATIONS 

Tlie  application  of  the  roentgen  ray  as  a  means  of 
diagnosis  of  pathologic  conditions  about  the  teeth  and 
jaws  is  a  method  that  has  achieved  a  x>osition  of  the 
utmost  importance  in  recent  years.  Its  value  has  long 
been  recognized  by  the  surgeon  in  the  diagnosis  of  the 
grosser  surgical  lesions  of  the  maxillary  bones,  such 
as  fractures,  tumors,  impacted  teeth,  etc.  Until  re- 
centty,  however,  the  dentist  in  general  practice  rarely 
found  it  necessar}^  to  resort  to  investigation  by  means 
of  the  x-ray.  At  the  present  time,  to  those  who  are 
familiar  with  its  advantages,  the  daily  employment  of 
this  agent  as  a  means  of  diagnosis  and  as  an  aid  to 
proper  treatment  has  become  indispensable. 

It  is  not  my  purpose  here  to  deal  with  the  knowledge 
necessary  for  the  making  of  roentgenograms,  involv- 
ing as  this  does  a  study  of  electricity,  theory  of  produc- 
tion of  x-rays,  a  description  of  x-ray  machines  and 
tubes,  etc.  What  is  of  far  more  importance  to  the 
average  dental  or  medical  practitioner  is  to  know  how 
to  interpret  roentgenograms  after  they  are  made.  Mis- 
takes are  frequently  made  by  tliose  having  an  inadequate 
knowledge  of  the  primary  essentials  which  will  presently 
be  discussed. 

17 


18  INTERPRETATION    OF    ROENTGENOGRAMS 

At  this  point  an  explanation  of  certain  terms  to  be 
used  in  the  book  is  in  order.  In  speaking  of  x-ray  pic- 
tures many  different  terms  are  employed,  such  as  roent- 
genogram, skiagraph,  skiagram,  radiograph,  etc.  The 
American  Koentgen  Ray  Societ}^,  which  may  be  properly 
taken  as  the  official  representative  of  this  branch  of  med- 
ical science  in  the  United  States,  has  adopted  in  honor  of 
Roentgen,  the  discoverer,  a  nomenclature  which  I  con- 
sider it  advisable  to  follow.  Thus,  in  speaking  of  an 
x-ray  picture  the  term  "roentgenogram"  is  to  be  pre- 
ferred. "Roentgenology"  is  preferable  to  "radiology." 
Certain  other  words  have  been  coined  for  the  sake  of 
brevit,y,  such  as  "stereogram,"  meaning  a  stereoscopic 
roentgenogram;  "pyelogram,"  a  roentgenogram  of  the 
pelvis  of  the  kidney  after  injection  with  some  salt  that 
resists  passage  of  the  rays.  In  the  same  way  the  term 
"odontogram"  is  here  suggested  for  a  roentgenogram 
depicting  the  teeth. 

Since  the  general  recognition  of  the  imx)ortant  rela- 
tionship of  infections  of  the  investing  tissues  of  the 
teeth  to  various  pathologic  conditions  of  the  body,  an 
examination  for  the  detection  of  the  cause  or  portal  of 
entry  of  many  generalized  infections  may  be  justly  re- 
garded as  incomplete  without  a  thorough  investigation 
of  the  teeth  and  surrounding  parts.  Since  serious  peri- 
apical dental  infection  may  be  present  in  the  entire  ab- 
sence of  subjective  or  objective  symptoms  or  history  of 
trouble,  every  examination  of  this  tyioe  should  include  a 
roentgenographic  study  of  all  crowned  and  pulpless 
teeth,  and  parts  of  the  alveolar  process  from  which  teeth 
are  apparently  missing.  The  necessary  cooperation  be- 
tween physician  and  dentist  in  eliminating  possible  foci 
of  infection  within  the  mouth  can  only  be  achieved 
through  an  ability  on  the  part  of  each  to  intelligently 
interpret  roentgen  ray  findings.  The  lack  of  dental 
knowledge  on  the  part  of  the  johysician  usually  leads  to 
unnecessary  sacrifice  of  teeth,  while  the  dentist's  igno- 


GENERAL    CONSIDEEATIOlSrS  19 

ranee  of  proper  roentgen  ra^^  interpretation  often  means 
ultraconservatism  with  consequent  danger  to  the  health 
of  the  patient.  The  importance  of  thorough  study  of  this 
subject  is  manifested  by  the  occurrence  of  cases  which 
baffle  even  those  of  great  experience  in  all  phases  of 
dental  diagnosis,  including  the  roentgen  ray. 

There  is  no  intention  here  to  intimate  that  every  den- 
tist should  be  equipped  with  an  x-ray  outfit  and  make  his 
o\^m  roentgenograms.  Most  men  have  not  the  time  to 
devote  in  which  they  can  acquire  a  mastery  of  the  sub- 
ject. In  the  average  individual  practice  there  is  not 
sufficient  variety  to  give  one  experience  in  interpretation. 
At  the  same  time,  dentistry  can  not  be  intelligently  or 
conscientiously  practiced  without  convenient  access  to 
this  method  of  diagnosis  at  least  in  all  cases  Avhere  root 
canal  operations  are  involved.  Where  the  dentist  him- 
self does  not  make  the  roentgenogram,  the  burden  of  in- 
terpretation should  not  fall  entirely  upon  the  roentgen- 
ologist, who  is  usually  without  knowledge  of  the  clinical 
conditions  of  the  individual  case  or  of  dental  pathology 
in  general.  Unless  he  has  had  experience  in  this  work  the 
dentist  should  not  attempt  to  read  the  roentgenogram 
without  help,  even  though  he  be  entirely  familiar  with 
the  clinical  aspects  of  the  case. 

In  the  following  pages  it  is  endeavored  to  point  out 
the  essentials  necessary  for  correctly  diagnosing  patho- 
logic conditions  about  the  teeth  with  the  roentgen  ray 
as  an  aid.  That  the  roentgen  ray  is  merely  an  aid  in 
arriving  at  this  diagnosis  can  not  be  too  strongly  empha- 
sized, and,  therefore,  a  proper  interpretation  of  a  roent- 
genogram can,  as  a  rule,  only  be  given  after  one  has 
gained  a  knowledge  of  certain  general  facts,  as  Avell  as 
special  data  pertaining  to  individual  cases  in  question. 

The  general  knowledge  necessary  for  the  correct  in- 
terpretation of  odontograms  comprises  the  foUoAving : 

1.  The  normal  anatomy  and  histology  of  the  teeth  and 
jaw  bones,  together  with  anatomic  variations. 


20  INTEKPEETATIOlsr    OF    EOEiSTTGEK^OGRAMS 

2.  The  appearance  that  the  roentgen  ray  should  impart 
to  plates  and  films  after  passage  through  such  normal 
tissues  and  anatomic  variations. 

3.  Special  dental  pathology  both  from  the  clinical  side 
and  the  histopathologic  side. 

After  mastering  these  three  essentials,  one  is  in  a  posi- 
tion to  take  up — 

4.  The  various  abnormalities  produced  in  the  roent- 
genogram by  disease. 

The  four  points  mentioned  will  be  discussed  more  in 
detail  in  subsequent  chapters.  After  acquiring  a  thor- 
ough familiarity  with  them,  it  is  hoped  that  the  student 
will  be  in  a  position,  with  the  aid  of  the  special  clinical 
facts  pertaining  to  the  individual  case,  to  make  use  of 
the  valuable  assistance  afforded  by  a'oentgenographic 
examination. 

Limitations  of  Roentgenography 

The  longer  one  is  engaged  in  this  work,  the  more  con- 
servative and  less  positive  he  becomes  in  giving  an  opin- 
ion as  to  what  is  represented  in  a  given  plate  or  film.  He 
begins  to  see  the  error  and  folly  of  calling  every  dark 
spot  at  the  end  of  a  tooth  root  an  ''abscess,"  which  in 
reality  is  found  less  commonly  than  some  other  abnormal 
conditions.  Like  everything  new,  the  roentgen  examina- 
tion of  the  teeth  has  been  overworked,  and  very  extrava- 
gant claims  have  been  made.  Based  upon  roentgenologic 
interpretation  by  workers  ignorant  of  dental  conditions, 
or  of  the  clinical  facts  in  individual  cases,  physicians  have 
ordered  the  wholesale  extraction  of  absolutely  healthy 
teeth.  The  failure  to  obtain  improvement  of  systemic 
complications  in  such  cases,  in  which  the  teeth  never  had 
any  bearing  on  the  question  at  all,  has  produced  a  reac- 
tion on  the  part  of  some  men,  who  question  the  value  of 
dental  roentgen  diagnosis  entirely,  an  opinion  that  is 
hailed  with  joy  by  some  nonprogressive  or  ultraconserva- 


GENERAL    CONSIDERATIONS  21 

tive  dentists  who  dislike  anything  that  is  likely  to  force 
a  change  in  their  obsolete  methods  of  practice. 

The  time  has  come,  however,  when  those  working  in 
this  field  are  in  a  position  to  state  with  some  assurance 
how  far  the  roentgen  ray  may  be  relied  upon.    We  must 
start  out  with  the  general  proposition  that  what  we  see 
in  a  roentgenogram  is  only  a  varied  gradation  of  shadow 
cast  by  the  rays  passing  through  substances  of  different 
density.    Speaking  strictly,  therefore,  Ave  can  only  say  in 
regard  to  dark  areas  on  the  negative  that  they  represent 
places  of  lessened  density,  which  allow  the  rays  to  pass 
through  more  easily  than  the  surrounding  parts.     This 
is  as  far  as  a  person  untrained  in  the  fundamental  prin- 
ciples mentioned  is  justified  in  giving  an  opinion.    What 
the  actual  contents  of  the  rarefied  areas  are,  we  can  sel- 
dom say  definitely  from  the  roentgenogram  alone,   al- 
though along  with  the  clinical  findings  and  history  we 
can  often  predict  with  some  assurance  as  to  what  will  be 
found  at  operation.    Even  in  the  absence  of  s^miptoms,  a 
periapical  rarefied  area  as  shown  in  the  odontogram  does 
mean  usually  that  disease  of  some  kind  is  present,  unless 
the  picture  has  been  made  shortly  after  operation  before 
the  area  has  had  time  to  become  obliterated.    The  state- 
ment has  been  frequently  made  by  some  eminent  authori- 
ties that  these  areas  of  rarefaction  shown  by  the  roent- 
gen ray  are  noninfective  in  the  absence  of  pain  and  local 
symptoms,  and  may  simply  represent  the  results  of  pve- 
viously  existing  disease  that  has  been  cured,  in  other 
words,  that  they  contain  harmless  scar  tissue.     While 
conceding  this  possibility  in  a  small  number  of  cases,  I 
believe  that  the  persistence  of  such  a  rarefied  area  for 
any  length  of  time  without  signs  of  decreasing  in  size  is 
sufficient  evidence  that  a  disease  process  is  going  on, 
otherwise  the  area  would  gradually  become  smaller  and 
be  replaced  by  new  bone.    There  is  abundant  postojDera- 
tive  x-ray  evidence  that  these  areas  of  rarefaction  disap- 


22  INTERPEETATIOISr    OF    ROENTGENOGRAMS 

pear  and  are  replaced  by  new  bone  unless  infection  re- 
mains. Operative  and  postoperative  pathologic  findings 
so  strongly  support  the  view  that  these  rarefied  areas 
as  shown  by  the  roentgen  ray  are  active  foci  of  disease  in 
most  cases,  that  in  our  opinion  it  is  the  wisest  course  to 
regard  them  as  diseased  until  proved  healthy,  especially 
in  invalids,  as  it  is  a  much  more  serious  matter  to  leave 
a  potential  source  of  systemic  infection  than  to  eradicate 
a  possibly  healthy  area. 

We  sometimes  hear  the  following  statement  made  by 
the  undul}^  conservative  skeptic  after  he  has  extracted  or 
has  had  extracted  teeth  shown  by  the  roentgen  ray  to  be 
responsible  for  periapical  bone  destruction :  '  ^  I  examined 
the  teeth  carefully  after  they  were  out,  and  there  was 
nothing  wrong  with  them."  In  other  words,  he  at- 
tempts to  convey  the  impression  that  owing  to  mistaken 
roentgen  diagnosis  the  teeth  were  unnecessarily  sacri- 
ficed, basing  his  opinion  on  a  casual  superficial  inspec- 
tion of  the  teeth  alone,  when  the  real  seat  of  the  disease 
was  located,  not  in  the  tooth  itself,  but  in  the  surrounding 
alveolar  process.  A  postoperative  opinion,  to  be  of  any 
value,  should  be  based  on  what  is  found  by  proper  curette- 
ment  of  the  rarefied  bone  about  the  apices  of  the  ex- 
tracted teeth,  including  perhaps  bacteriologic  and  his- 
tologic study  of  the  tissue  removed.  Because  there  is  no 
visible  absorption  or  exostosis  of  the  root,  no  fluid  pus, 
or  no  so-called  '' abscess  sac"  adherent  to  the  root  when 
it  is  extracted,  this  does  not  necessarily  mean  that  no 
disease  is  present  in  the  surrounding  bone. 

While  we  can  never  say  absolutely  from  the  odonto- 
gram what  constitutes  the  contents  of  these  rarefied  peri- 
apical bone  areas,  yet  a  study  of  the  picture  often  reveals 
points  that  enable  us  to  make  at  least  a  tentative  diag- 
nosis. Thus,  a  round  or  oval  area  of  bone  rarefaction 
with  very  sharply  defined  regular  edges,  and  which  per- 
mits practically  complete  passage  of  the  rays,  is  fairly 


GElsrEEAL    CONSIDERATIOlirS  23 

good  evidence  that  a  cyst  is  present.  On  the  other  hand, 
an  area  with  ill-defined  edges,  merging  almost  imj)ercep- 
tibly  with  the  surrounding  healthy  bone,  and  in  most  of  its 
parts  offering  at  least  some  resistance  of  the  passage  of 
the  rays,  is  indicative  of  the  presence  of  a  more  or  less 
active  suppurative  process.  Between  these  two  extremes 
we  find  various  gradations,  among  which  may  be  placed 
cases  of  granuloma.  The  size  of  an  area  of  suspected 
abnormality  has  no  relation  to  its  character  or  jDatho- 
genicity.  Disease  may  be  present  without  pus.  Absence 
of  an  abnormal  roentgenographic  area  does  not  necessa- 
rily mean  that  the  tissue  must  be  healthy.  A  tooth  may 
contain  infected  necrotic  pulp  tissue,  giving  rise  to  sys- 
temic involvement,  yet  show  no  evidence  of  bone  rare- 
faction in  the  odontogram.  A  sinus  discharging  pus  may 
be  present,  yet  there  may  be  insufficient  periapical  bone 
rarefaction  or  destruction  to  be  demonstrable  by  the 
roentgen  ray.  We  frequently  find  at  operation  condi- 
tions much  worse  than  depicted  in  the  odontogram,  so 
that  the  latter  often  underestimates  and  seldom  exag- 
gerates the  amount  of  disease  present. 

Localization 

Eoentgenograms  as  ordinarily  made  do  not  give  any 
perspective,  and  it  is  generally  impossible  in  such  pic- 
tures to  determine  the  relative  positions  of  given  parts 
of  the  objects  shown  except  in  two  dimensions.  We  have 
two  means  of  gaining  a  better  idea  of  the  relative  posi- 
tions of  objects  hidden  from  view  by  the  tissues,  such  as 
roots  of  teeth,  etc.  The  simplest  is  by  making  two  or 
more  odontograms  in  different  positions,  and  comparing 
the  different  pictures.  The  other  method  is  by  stereo- 
roentgenography; i.  e.,  making  two  views  with  the  plate 
or  film  and  the  object  in  the  same  relative  positions,  but 
with  the  rays  at  different  angles,  perspective  being  gained 
by  merging  the  two  images  in  the  stereoscope.  These  two 
methods  will  be  described  in  another  chapter. 


CHAPTEE  II 

ANATOMY    OF    THE    TEETH   AND    JAWS,    WITH 

SPECIAL  REFERENCE  TO  ROENTGENOGRAM 

INTERPRETATION 

In  the  passage  of  the  roentgen  ra3^s  through  the  tis- 
sues, the  denser  the  tissue  the  greater  the  obstruction 
offered  to  the  rays,  and  consequent!}'  the  lighter  will  be 
the  image  in  the  negative. 

In  roentgenograms  of  the  jaws,  the  substances  depicted 
in  the  order  of  their  density,  beginning  with  the  densest, 
and  therefore  the  lightest  in  the  negative,  are: 

1.  Metallic  crowns  and  fillings,  and  root  canal  fillings 
containing  zinc  or  other  metals. 

2.  Enamel  of  the  teeth. 

3.  Dentine. 

4.  Cementum. 

5.  Cortical  bone.  •  ^ 

6.  Cancellated  bone. 

7.  Medullar}^  spaces,  canals,  foramina  in  bone,  and  soft 
tissues. 

In  disease,  the  normal  condition  of  a  given  tissue  may 
be  changed  either  to  a  lessening  in  densitj^,  meaning 
abstraction  of  lime  salts,  with  consequent  deepening  of 
the  shadow  in  the  x-ray  negative,  or  an  increase  in  den- 
sity, due  to  a  deposit  of  lime  salts,  and  indicated  by  a 
lessening  of  the  shadow. 

A  familiarity  with  the  anatomy  of  the  teeth  and  jaw 
bones  is  one  of  the  fundamental  essentials  for  correct 
interpretation  of  odontograms.  Lack  of  this  knowledge 
is  frequently  a  cause  of  mistaking  of  normal  shadows  for 
manifestations  of  disease. 

24 


ANATO:\IY    OF    THE    TEETH    AXD    JAWS 


25 


The  tooth  are  set  in  sockets  in  the  alveohir  jDrocess, 
being  attached  by  the  peridental  membrane.  The  alveolar 
process  is  composed  of  spongy  or  cancellated  bone  (Fig. 
1),  which  appears  in  the  roentgenogram  as  a  fine  inter- 
lacing network.  The  sockets  of  the  teeth  are  lined  with 
a  thin  plate  of  dense  bone,  which  is  shown  in  the  x-ray 


-,.00^  .m\ 


V-- 


#N 


IN 


J 


*• 


'^  ■■■■■"• 


,  ,«»<-.•■" 


Fig.    1. — Showing  cancellated  bone  of  alveolar  process.      (Cryer.) 

negative  as  a  fine  white  line  around  the  tooth.  Between 
this  line  and  the  tooth  itself  is  a  narrow  dark  space  rep- 
resenting the  peridental  membrane.  These  lines  are  im- 
portant landmarks  in  the  interpretation  of  odontograms, 
as  their  absence  or  deviation  vsuaUi/  means  some  patho- 
logic condition.     (See  Fig.  39,  p.  79.) 


26 


INTERPRETATION    OF    ROENTGENOGRAMS 


Roentgenographic  Anatomic  Landmarks  in  the  Upper 
and  Lower  Jaws 

Upper  Jaw 

At  a  varying  distance  above  tlie  apices  of  the  central 
and  lateral  incisor  teeth  is  fonnd  the  iloor  of  the  nose 
(Fig.  2),  sometimes  seen  in  the  odontogram  as  a  dark 


Fig.   2. — Anterior  view  of  skull,  showing  anterior  opening  of  nasal  chamber.      (Cryer.) 

shadow  which  might  be  mistaken  for  a  cj^stic  or  abscess 
cavity  in  the  bone  (Figs.  47  and  48,  p.  81). 

Above  the  apices  of  the  premolar  and  molar  teeth  is 
found  the  maxillary  sinus  or  antrum  of  Highmore.  This 
sinus  varies  very  much  in  its  extent,  shape,  and  in  the 
relation  of  its  floor  to  the  roots  of  the  teeth.  Sometimes 
there  is  a  considerable  thickness  of  bone  between  the  tooth 
apices  and  the  sinus  (Fig.  3).    In  other  cases  the  tooth 


ANATOMY    OF    THE    TEETH    AND    JAWS 


27 


apices  come  right  up  to  the  floor  of  the  sinus,  even  form- 
ing projections  into  the  cavity,  though  under  normal  con- 
ditions always  separated  from  it  by  a  thin  lamina  of  bone 
(Fig.  4).    Sometimes  the  ends  of  the  roots  are  found  well 


Fig.   3. — Showing    considerable    thickness    of    bone    between    the    apices    of    the    molar 
roots  and  the   mamillary   sinuses.      (Cryer.) 


Fig.   4. — Showing  smooth   prominences   in   floor   of   maxillary   sinus   overlying  apices   of 
roots   of   premolar   and   molar  teeth.      (Cryer.) 

above  the  most  dependent  portion  of  the  sinus,  but  lo- 
cated in  its  wall  (Fig.  5).  The  floor  of  the  maxillary 
sinus  is  usually  found  in  relation  to  the  roots  of  the  molar 


INTERPRETATIOlSr    OF    EOENTGENOGRAMS 


1 11  bt  molai 


1  1   -^t   molai 


Fig.   S. — Showing  floor  of  maxillary  sinus  dipping  down  between  roots  of  molar  tooth, 
the   apices   thus   being   above   the   level   of   the  floor.      (Cryer. ) 


Infraorbital  sinus 


Infraorbital  foramen 


d  passing  through 
infraorbital 
canal   and    foramen. 


Maxillary    sinus. 


Opening  caused  by  apical 
abscess. 


Fig.   6. — In   this   specimen   the   maxillary    sinus   does   not   extend   much   anterior   to   the 
first  molar.      (Cryer.) 


ANATOMY    OF    THE    TEETH    AITD    JAWS 


29 


teeth  (Fig.  6),  but  ma}^  extend  as  far  forward  as  the 
first  premolar  or  canine  (Fig.  7).  These  varying  rela- 
tions of  the  floor  of  the  antrum  of  Highmore  to  the  roots 
of  the  teeth  are  well  shown  in  x-ray  negatives,  the  cavity 
of  the  antrum  appearing  as  a  dark  shadow  wliicli  must 


I'ig.   7. — Here  the  floor   of   the   maxillary   sinus   extends   in   front  as   far   as   the   region 
of  the  first  premolar  tooth.      (Cryer.) 


not  be  mistaken  for  a  rarefied  disease  area.  It  is  some- 
times difficult  in  the  study  of  odontograms  of  this  region 
to  determine  whether  or  not  the  roots  of  the  teeth  project 
into  the  maxillary  sinus  and  whether  areas  of  absorption 
about  the  roots  communicate  with  it.    In  the  odontogram, 


dU  INTERPEETATION'    01^    EOE:N"TGE]SrOGRAMS 

where  a  root  is  projected  above  the  level  of  the  floor  of 
the  antrum,  it  is  important  to  seek  carefully  the  dark  and 
light  lines  found  around  normal  teeth  in  order  to  dif- 
ferentiate the  normal  condition  shown  in  Figs.  5,  87,  and 
89,  p.  91,  from  pathologic  conditions  in  which  roots  com- 
municate with  the  cavit}^  of  the  sinus. 
FoRAMiivrA,   Caitals,  Etc. — In   the  upper  jaw,   on  tlie 


Fig.  8. — Showing  anterior  palatine  fossa  just  behind  and  between  the  upper 
central  incisor  teeth.  The  posterior  palatine  canal  is  seen  as  a  groove  running 
parallel    to    and    just    within    the    line    of    the    molar    teeth.      (Cryer.) 


palatal  surface  just  behind  and  between  the  central  in- 
cisor teeth  is  found  the  anterior  palatine  fossa  (Fig.  8). 
This  contains  foramina  carrying  blood  vessels  and  nerves 
from  the  nose.  In  roentgenographic  films  of  the  anterior 
teeth  this  fossa  is  frequently  seen  as  a  dark  shadow  above 
and  between  the  apices  of  the  central  incisors,  and  when 


A]SrATOMY    OF    THE    TEETH    AXD    JAAVS  61 

in  close  relation  to  roots  of  teeth  under  suspicion,  miglit 
be  mistaken  for  rarefaction  due  to  disease  of  the  bone 
(Fig.  41,  p.  79). 

The  posterior  palatine  canal  (Fig.  8),  is  found  in  the 
form  of  a  groove  running  posteroanteriorh'  in  the  roof 
of  the  mouth  mesially  to  the  molar  teeth.  In  the  roent- 
genographie   film   it  is   occasionally   shown   as   a  dark 


Fig.   9. — Showing  cancellated   internal   stiaicture   of   mandible  with  mental    foramen  be- 
low  and   lietween  roots   of   premolar   teeth.      (Cryer.) 

shadow  in  the  wall  of  the  antrum  in  close  relation  to  the 
palatal  roots  of  the  molar  teeth. 


Lower  Jaw 

Here  the  iDrincipal  roentgenograiDhic  anatomic  land- 
marks are  the  mandibular  canal  and  the  mental  foramen 
(Fig.  9).  The  mandibular  canal  runs  posteroanteriorly 
below  the  apices  of  the  teeth,  and  sometimes  in  very  close 
relationshix)  with  them.  (Fig.  10.)  In  the  roentgeno- 
gram the  root  of  a  lower  molar  may  apparently  project 
into  the  dark  space  representing  tlie  canal,  yet  in  reality 
be  situated  to  one  side  or  the  other. 


32 


IlvFTERPEETATION    OF    EOENTGENOGRAMS 


The  mental  foramen,  situated  below  and  between  the 
lower  premolar  teeth,  may  easily  be  mistaken  for  an 
area  of  disease  associated  with  one  of  these  teeth,  par- 


Fig.  10. — Plate  of  right  side  of  face,  with  head  placed  especially  to  show  molar 
region.  Horizontal  impaction  of  lower  third  molar.  (See  Fig.  11.)  Mandibular 
canal    seen    below    this    tooth. 


ticularly  if  there  are  clinical  signs  giving  a  suspicion  of 
trouble  (Fig.  176,  p.  113).  Very  frequently,  however, 
the  connection  of  the  mental  foramen  with  the  inferior 
dental  canal  can  easily  be  seen  in  the  roentgenogram 
(Fig.  182,  p.  115). 
In  hlms  of  the  upper  premolar  and  molar  region  the 


ANATOMY    OF    THE    TEETH    AXD    JAWS  66 

overhanging  malar  bone  frequently  casts  a  shadow  which 
obscures  the  roots  of  these  teeth  (Figs.  127  and  128, 
p.  101). 


Fig-.  11. — iTtiagrammatic  illustratioi)  ■'  i  j;  10.  a.  Portion  of  iower  jaw  overlapped 
by  shadow  of  opposite  side;  b,  vertebiv.  >.  maxillary  sinus  and  nasa'  lossa;  d,  ;i>gion 
of   ethmoid   cells;    e,   mandilnilar   ca;.al;    r,   liyoi<l   bom^;   .'/,   "ondyle   r,    mandililo. 


Anatomic  Landmarks  in  Roentgenographic  Plates 
of  the  Jaws 

In  a  iai  Mai  roentgenographie  plate  of  tlie  upper  and 
lower  jaws,  made  with  the  head  in  the  position  shown  in 
Fig.  24,  attention  is  called  to  certain  anatomic  landmarks, 
Avhich  are  shown  in  Figs.  10  and  12,  and  diagrannnat- 


34  IlSrTEEPRETATION    OF    ItOENTGEJsrOGRAMS 

ieally  in  Figs.  11  and  13.  The  upper  and  lower  teeth  of 
the  side  examined  are  nsnally  well  shown  from  the  third 
molars  forward  to  the  canines.  In  the  anterior  portion 
of  such  a  plate,  the  shadow  of  the  opposite  side  of  the 
jaw^s  overlies  that  of  the  side  nearest  the  plate,  the 
amonnt  of  overlapping  depending  on  whether  the  pa- 
tient's nose  is  pressed  down  on  the  plate  or  slighth' 


Fig.   12. — Plate    of    left    side    of    face,    showing    normal    anatomic    landmarks    and    im- 
pacted  upper  third   molar.      (See   Fig.    13.) 

raised  from  it.  In  the  same  way  the  position  of  the  head 
affects  the  overlapping  of  the  molar  region  by  the 
shadows  of  the  vertebrae  at  the  posterior  portion  of  the 
plate.  The  dark  space  above  the  npper  teeth  is  formed 
by  the  maxillary  sinus  and  the  nasal  fossa.  Into  this 
space  occasionally  may  be  seen  projecting  the  coronoid 
process  of  the  opposite  side  of  the  ,]*aw„  Above  the 
maxillary  sinus  and  nasal  fossa,  the  honeycombed  ap- 
pearance is  due  to  the  ethmoid  cells.    Below  the  roots  of 


ANATOMY    OF    THE    TEETH    AXD    JAWS 


35 


the  loAver  molar  teeth  maj^  be  seen  the  mandibular  canal, 
running  forward  to  the  mental  foramen  lietween  and  be- 
low the  apices  of  the  premolars.  Below  the  lower  border 
of  the  mandible,  extending  in  front  of  the  vertebrae  as 
far  forward  sometimes  as  the  first  molar,  the  hyoid  bone 


Fig.  13. — Diagrammatic  illustration  of  Fig.  12.  a,  portion  of  upper  and  lower- 
jaws  overlapped  by  shadow  cf  opposite  side;  b,  vertebrre;  c,  maxillary  sinus  and  nasai 
fossm;  d,  coronoid  process  of  right  side  of  mandible;  e,  mandibular  canal;  /,  mental 
foramen;  g,  hyoid  bone. 

is  sho^^m.  In  plates  taken  to  show  the  molar  region,  the 
ramus  and  cond^doid  process  of  the  mandilile  can  fre- 
quently be  traced  up  to  the  joint. 


CHAPTER  III 

PATHOLOGY  IN  RELATION  TO  DENTAL 
ROENTGENOLOGY 

One  of  the  essentials  of  correct  interpretation  of  roent- 
genograms of  the  teeth  and  their  supporting  tissues  is  a 
familiarity  with  the  clinical  course,  pathology,  and  result 
of  acute  and  particularly  chronic  inflammation  involving 
these  parts.  The  diagnostic  value  of  the  roentgen  ray  iu 
inflammatory  processes  affecting  the  teeth  and  surround- 
ing parts  depends  entirely  upon  variations  in  the  density 
of  the  hard  tissues  as  a  result  of  the  inflammation.  In  an 
acute  localized  infection,  confined  to  one  tooth,  the  inflam- 
matory process  usually  is  of  too  short  duration  to  bring 
about  an  appreciable  amount  of  destruction  of  bone  tis- 
sue, and  the  roentgen  ray  is  often  of  slight  aid  in  a  case 
of  this  kind.  It  is  in  the  chronic,  long-standing  types  of 
infection,  or  in  an  acute  process  grafted  upon  a  chronic 
one  that  this  method  of  diagnosis  finds  its  greatest  field 
of  usefulness. 

From  a  clinical  and  a  pathologic  standpoint  there  are 
in  general  two  types  of  lesions  about  the  teeth  in  which 
examination  by  the  roentgen  ray  is  an  aid  to  diagnosis 
and  prognosis.    These  are : 

1.  Lesions  involving  the  periapical  region  of  the  tooth 
dependent  upon  infection  following  death  of  the  pulp. 

2.  Lesions  involving  the  investing  tissues  of  the  teeth — 
the  peridental  membrane  and  alveolar  process — not  de- 
pendent upon  death  of  the  dental  pulp,  but  in  which  the 
infection  starts  at  the  gingival  margin,  so-called  pyor- 
rhea alveolaris,  or  more  correctly,  chronic  suppurative 
osteopericementitis. 

36 


PATHOLOGY   AND    DENTAL    ROENTGENOLOGY  37 

A  third  type  of  lesion  is  occasionally  seen,  the  so-called 
pericemental  abscess,  in  which  an  inflammatory  process 
is  set  up  in  the  pericementum  of  a  tooth,  independently 
of  disease  of  the  pulp,  the  latter  retaining  its  vitality,  or 
being  only  secondarily  involved.  In  these  lesions  the 
infecting  organisms  usually  gain  entrance  from  the  gum 
margin,  or  from  neighboring  diseased  teeth,  but  may  be 
carried  from  other  parts  of  the  body  through  the  blood 
stream. 

Periapical  Dental  Lesions 

Lesions  of  this  type  are  the  most  important  with  which 
we  have  to  deal  from  a  roentgenologic  standpoint,  because 
they  often  occur  in  the  absence  of  clinical  symptoms  or 
signs,  when  roentgen  examination  becomes  the  principal 
means  of  diagnosis. 

In  the  vast  majority  of  cases  of  this  type  the  disease 
results  from  infection  following  death  of  the  dental  pulp, 
the  causative  bacteria  passing  up  the  root  canal  and  gain- 
ing access  to  the  periapical  tissues  through  the  apical 
foramen  of  the  tooth.  Bacteria  may  also  in  a  small  per- 
centage of  cases  be  carried  by  the  blood  stream  from 
other  parts  of  the  body  and  lodged  in  the  periapical  tis- 
sues of  pulpless  teeth  or  teeth  containing  necrotic  pulp 
tissue.  This  infection  may  follow  dental  caries  and  in- 
flammation and  death  of  the  pulp,  traumatism,  or  arti- 
ficial devitalization  by  the  dentist.  The  use  of  arsenic 
for  pulp  devitalization,  and  the  forcing  of  strongly  irri- 
tating medicinal  agents  such  as  formaldehyde  into  the 
periapical  region  are  important  predisposing  factors  in 
leading  to  infection.  Much  has  been  said  about  the  part 
played  by  various  medicinal  chemical  irritants  in  the 
causation  of  these  periapical  conditions.  It  is  eas}^  to 
understand  how  such  chemicals  can  be  the  starting  point 
preparing  the  way  for  bacterial  infection,  but  that  they 
alone  can  induce  a  reactive  process  such  as  examination  of 


38  INTERPRETATION    OF    ROENTGENOGRAMS 

these  diseased  tissues  reveals,  continuing  and  progress- 
ing perhaps  for  years,  is  inconceivable,  inasmuch  as  these 
chemical  agents  are  limited  in  the  duration  of  their  action 
by  the  fact  that  they  can  not  perpetuate  themselves.  It 
is  only  by  the  addition  of  a  vital,  self -propagating  factor, 
that  is,  living  bacteria,  that  such  a  long-standing  inflam- 
matory reaction  can  be  explained.  This  view  is  con- 
firmed by  histologic  and  bacteriologic  examination  of  the 
tissues  involved.  So  we  must  regard  infection  by  living 
bacteria'  as  the  essential  cause  of  long-standing  peri- 
apical lesions. 

Failure  on  the  part  of  the  dentist  to  observe  absolute 
asepsis  in  performing  root  canal  operations  is  a  frequent 
means  of  introducing  streptococci  from  the  mouth  sur- 
face into  the  periapical  tissues.  The  original  infection  in 
practically  all  cases  of  periapical  disease  is  streptococcal. 
It  is  unnecessary  here  to  discuss  at  length  the  work  of 
Rosenow,  Gilmer,  and  Moody,  Hartzell  and  Henrici,  and 
others,  bearing  upon  this  question. 

The  access  of  streptococci  to  the  peridental  membrane 
of  the  apical  region  in  one  of  the  ways  mentioned,  causes 
a  typical  inflammatory  reaction  on  the  part  of  the  tissues, 
which  is  dependent  upon  the  virulence  of  the  invading 
organisms  and  the  resistance  of  the  patient.  If  the  strep- 
tococcus is  of  the  hemolytic  type,  of  high  virulence,  and 
the  patient's  resistance  is  low,  the  inflammation  is  acute, 
and  may  result  in  acute  abscess  formation.  If  this  occurs, 
after  evacuation  of  the  pus,  and  under  proper  treatment, 
the  condition  may  rapidty  subside  with  practically  no 
detachment  or  destruction  of  the  peridental  membrane, 
and  no  appreciable  destruction  of  bone. 

In  case  the  invading  organism  is  of  the  viridans  type, 
of  low  virulence,  the  infiammatoiy  reaction  is  apt  to  be 
chronic,  giving  rise  to  little  apparent  disturbance,  but 
slowly  progressive  and  proliferative  in  nature.  The  first 
change  seen  in  the  peridental  membrane  is  a  thickening 


PATHOLOGY    AI^D    DEjSTTAL    EOEjSTTGENOLOGY  39 


-Inflammatory    periapical    tissue    of    the    more    acute    type,    showing    prepon- 
derance   of    polymorphonuclear    cells. 


Fig.  15. — Chronic  type  of  periapical  inflammation.  Preponderance  of  small  round 
cells.  Capillary  blood  vessels  are  seen,  establishing  a  connection  between  the  focus 
o£   infection  and  the  general  circulation. 


40  INTEEPEETATIOX    OF    EOENTGEjSI^OGEAMS 

of  this  tissue,  which  is  infiltrated  with  various  blood  ele- 
ments, but  especially  polymorphonuclear  and  small  round 
cells,  particularly  the  latter  (chronic  proliferative  peri- 
cementitis). This  peridental  thickening  takes  place  at 
the  expense  of  the  bone  of  the  alveolar  process,  and  as 
proliferation  of  round  cells  occurs,  the  bone  becomes  rare- 
fied and  finally  destroyed  (chronic  rarefying  osteitis), 
leaving  a  space  filled  with  a  mass  of  chronic  inflamma- 
tory granulation  tissue,  the  so-called  granuloma.  The 
granuloma  is  composed,  therefore,  of  small  round  cells, 
polymorphonuclear  and  endothelial  leucocytes,  foreign- 
body  giant  cells,  fibroblasts,  capillaries,  and  fibrous  tissue, 
and  sometimes  masses  of  epithelial  cells,  to  Avhich  atten- 
tion Avill  be  called  later.  From  this  tissue  streptococci 
may  be  obtained  both  by  direct  smear  and  by  culture. 
The  histologic  appearance  of  the  tissue  varies  with  the 
virulence  of  the  infecting  organism,  the  more  virulent 
types  of  infection  and  those  of  short  duration  giving  a  pre- 
ponderance of  polymorphonuclear  cells  (Fig.  14),  the  more 
chronic  types  of  infection  showing  few  pol^miorphonu- 
clears  but  many  small  round  cells  (Fig.  15),  while  in  cases 
of  long  standing,  the  cellular  elements  are  few,  and  fibrous 
tissue  predominates  (Fig.  16).  Sometimes  the  granula- 
tion tissue  breaks  down,  and  is  replaced  b}^  fluid  pus 
which  fills  the  bone  cavity  {chronic  abscess),  or  the  con- 
tents may  consist  partially  of  pus  and  partially  of  granu- 
lation tissue  {suppurating  granuloma).  Such  lesions  con- 
taining fluid  pus,  however,  are  in  a  considerable  minorit}^, 
as  compared  to  the  solid  or  semisolid  granuloma,  and, 
therefore,  the  term  ''chronic  abscess"  is  entirely  inap- 
plicable in  the  great  majority  of  cases  of  periapical 
infection. 

These  areas  of  bone  rarefaction  and  destruction  vary 
greatly  in  size.  The  bone  absorption  is  usually  accom- 
panied by  a  slow  detachment  and  destruction  of  the  peri- 
dental membrane  covering  the  cemcntum  at  the  root  end. 


PATHOLOGY   AND    DENTAL   ROENTGENOLOGY 


41 


Fig.     16. — Case     of    long-btamling     periai->ical     inflammation, 
preponderance    of    fibrous   tissue. 


showing     fewer    cells    and 


Fig.    17. — Mass    of    squamous    epithelial    cells     (debris    epitheliaux    paradentaircs) 
bedded    in    chronic    periapical    inflammatory    tissue. 


42  INTEEPEETATIOISr    OF    EOENTGENOGRAMS 

thus  depriving  the  latter  of  its  blood  supply,  and  con- 
verting it  into  a  necrotic  foreign  body. 

Coincident  with  the  chronic  abscess  or  granuloma  for- 
mation, rarefaction  and  absorption  of  the  necrotic  cemen- 
tum  of  the  root  apex  takes  place  by  the  action  of  endo- 
thelial leucocytes  and  foreign-body  giant  cells.  This  is 
usually  accompanied  by  the  production  of  new  cementum 
by  cementoblasts  that  have  not  been  destroyed,  forming 
irregular  thickenings  of  the  root.  Sometimes  this  hyper- 
cementosis  is  the  principal  lesion  found. 

The  contents  of  the  spaces  produced  hy  periapical  bone 
absorption,  including  bacteria  and  their  products,  have 
direct  connection  ivith  the  general  circulation  through 
capillary  blood  vessels  and  lymphatics  in  the  ivalls  of  the 
cavities  and  running  in  all  directions  through  the  granu- 
lation tissue.  While  the  outer  layers  of  the  granuloma 
may  be  denser  and  more  fibrous  than  its  inner  portion, 
there  is  no  limiting  membrane  in  the  sense  of  preventing 
its  contents  from  entering  the  general  circulation. 

After  eradication  of  infection  in  a  periapical  bone  area, 
new  bone  is  usually  formed,  filling  in  the  space  after  sev- 
eral months.  The  space  at  first  contains  blood  clot,  which, 
if  sterile,  organizes  into  fibrous  connective  tissue.  Then 
the  bone  cells  of  the  surrounding  alveolar  process  deposit 
lime  salts,  the  density  gradually  increasing  until  normal 
bone  is  the  result.  Occasionally  this  new  bone  is  much 
denser  than  normal,  due  to  excessive  deposit  of  lime 
salts,  and  is  shown  in  the  odontogram  as  a  light  area. 
This  dense  bone,  by  pressure  on  sensory  nerve  filaments, 
may  cause  neuralgia. 

Cyst  Formation 

Among  the  connective  tissue  elements  of  the  inflamma- 
tory granuloma  developing  as  a  result  of  infection  about 
the  root  apex  are  frequently  found  masses  of  squamous 
epithelial  cells  (Fig.  17).     Similar  cells  are  present  nor- 


PATHOLOGY   AIS^D    DENTAL    ROENTGENOLOGY 


43 


Via 


18. — Early   stage   of   cyst   formation,   showing-   cavity   lined   with    several   layers    of 
epithelium,    with    chronic   inflammatory   tissue    at    the   periphery. 


Fig.    19. — High    power    view    of    epithelial    cyst    lining. 


44  interpeetatioisj'  of  eoentgenogeams 

iiially  in  the  peridental  membrane,  where  they  are  known 
as  debris  epitJieliaux  paradentaires  of  Malassez.  These 
epithelial  cells  are  believed  to  be  remains  of  the  outer 
cells  of  the  enamel  organ  which  originally  passed  down 
and  formed  the  outer  wall  of  the  sac  in  which  the  cemen- 
tum  of  the  root  was  formed.  Proliferation  of  these 
epithelial  cells  found  among  the  granulation  tissue  is 
stimulated  by  the  chronic  inflammatory  process.     The 


Fig.   20. — Later  stage  of  cyst  formation,  showing  pressure  atrophy   of  epithelial   lining. 

mass  of  epithelium  then  breaks  down  in  the  center,  it  is 
believed  by  fatty  degeneration,  and  a  space  is  formed 
containing  fluid  (Figs.  18  and  19).  This  cyst  cavity  grad- 
ually enlarges,  the  pressure  of  the  fluid  causing  atrophy 
of  the  epithelial  cells,  until  the  wall  of  the  cyst  consists 
of  a  dense  fibrous  capsule  lined  with  at  most  a  few  layers 
of  epithelial  cells  (Fig.  20).  All  traces  of  epithelium  may 
finally  disappear.    The  cyst  fluid  is  usually  clear,  straw- 


PATHOLOGY   AND    DE]SrTAL   EOENTGE]S!'OLOGY  45 

colored,  and  may  contain  cliolesterin  crystals,  recognized 
by  their  rectangular  shape  with  a  notch  in  one  angle.  The 
fluid  is  generally  sterile,  but  infection  of  the  cyst  wall 
may  convert  it  into  pus  from  which  various  organisms 
may  be  recovered.  Dental  root  cysts  may  vary  con- 
siderably in  size,  from  that  of  a  small  pea  to  a  hen's  egg 
(Figs.  217  and  243).  In  the  maxilla,  they  may  invade  the 
maxillary  sinus  or  the  nasal  fossa  (Fig.  241).  Cyst  for- 
mation, contrary  to  the  opinion  of  some  authors  (Thoma), 
is  common  in  connection  with  periapical  infection.* 

Stages  of  Periapical  Disease  in  Relation  to  Roentgeno- 
graphic  Abnormalities 

The  principal  stages  of  chronic  periapical  disease  giv- 
ing rise  to  roentgenographic  abnormalities  may  be 
summed  up  as  follows: 

1.  Chronic  Proliferative  Pericementitis,  producing 
a  slight  thickening  of  the  peridental  membrane  aliout  the 
tooth  apex,  but  without  appreciable  loss  of  bone.  In  the 
odontogram  this  is  shown  by  an  increase  in  thickness  of 
the  normal  dark  line  between  the  apical  portion  of  the 
tooth  root  and  the  bone. 

2.  Chronic  Karefying  Osteitis  with  Granuloma. — A 
slow  disintegration  of  bone  takes  place  in  a  circum- 
scribed area  about  the  tooth  apex,  the  bone  tissue  being 
replaced  by  granulation  tissue.  The  tooth  apex  may 
project  into  the  bone  cavity,  may  be  shortened  or  rough- 
ened from  irregular  absorption  of  the  cementum,  or  may 
present  enlargements  due  to  hypercementosis.  In  the 
roentgenogram  these  lesions  are  shown  as  more  or  less 
clearly  defined  areas  of  lessened  density;  i.  e.,  darker  than 

*For  a  more  detailed  description  of  the  histopathology  of  chronic  periapical  dis- 
ease with  a  complete  review  of  the  literature  of  the  subject,  the  reader  is  referred 
to  the  article  by  Henrici  and  Hartzell  in  the  Journal  of  the  National  Dental  Associa- 
tion,   1917,    iv,    1061. 


46  INTERPRETATIOlSr    OF    EOEiSTTGENOGRAMS 

the  surroundiiLg  bone.    The  irregular  form  of  the  apical 
end  of  the  tooth  root  is  also  shown  when  present. 

3.  Cheo^^ic  Rarefying  Osteitis  witpi  SuppuRATioisr. — '■ 
Here  we  have  an  area  of  bone  destruction  in  which  the 
space  is  entirely  or  j)artly  filled  with  fluid  pus.  The 
apical  peridental  membrane  is  nearly  always  destroyed, 
the  root  end  roughened,  with  the  necrotic  cementum 
bathed  in  pus.  The  infection  in  this  type  of  lesion  is  to 
be  regarded  as  more  active  than  in  the  preceding  form. 
The  roentgenogram  presents  a  blurred  area  of  somewhat 
lessened  density  compared  with  the  surrounding  bone, 
with  irregular  and  ill-defined  margins,  into  which  the 
roughened  tooth  apex  projects.  The  more  active  the 
suppurative  process,  the  more  irregular  and  ill-defined 
will  be  the  margins  of  the  lesion  in  the  odontogram. 

4.  Cheoi^ic  Rareeyixg  Osteitis  with  Cyst  Foematioi^. 
— This  stage  succeeds  that  of  granuloma,  the  cavity  in  the 
bone  being  filled  with  clear  fluid  and  often  little  soft  tis- 
sue except  a  thin  fibrous  sac.  In  the  roentgenogram, 
therefore,  the  cyst  appears  as  a  very  clearly  defined  dark 
area  involving  the  apices  of  one  or  more  teeth.  The 
margins  are  regular  and  very  sharply  defined,  so  that 
there  is  usually  no  difficulty  in  telling  exactly  where  the 
health}^  bone  ends. 

The  basis  for  the  foregoing  classification  consists  in 
roentgenographic  examinations  checked  up  by  subse- 
quent extraction  of  teeth  or  surgical  treatment  followed 
by  histologic  and  bacteriologic  examination. 

Infection  of  the  Investing  Tissues  of  the  Teeth  Beginning" 
at  the  Gingival  Margin — Pyorrhea  Alveolaris 

For  a  detailed  discussion  of  the  etiology  and  pathology 
of  chronic  suppurative  pericementitis  or  pyorrhea  alveo- 
laris the  reader  is  referred  to  Black's  ''Special  Dental 
Pathology,"  and  other  works.    Only  such  points  will  be 


PATHOLOGY    AXD    DEISTTAL    EOEXTGEXOLOGY  47 

taken  up  here  as  have  a  direct  bearing  upon  roentgen 
diagnosis. 

This  disease  always  begins  as  a  gingivitis  due  to  irri- 
tation of  the  gum  about  the  necks  of  the  teeth.  Among 
these  irritating  factors  may  be  mentioned:  malocclusion, 
involving  misapplied  stress  in  mastication;  improper  con- 
tact of  teeth  produced  by  faulty  restorative  operations, 
permitting  the  wedging  of  food  between  the  teeth  with  im- 
pingement upon  the  gum  septum;  imperfect  margins  of 
crowns  and  fillings,  either  pressing  upon  the  gum  tissue 
or  permitting  lodgment  of  food ;  lack  of  cleanliness,  allow- 
ing deposition  of  calculus  and  food.  Any  of  these  causes 
will  produce  a  local  injury  to  the  gum  tissue,  and  permit 
infection  by  the  microorganisms  always  present  in  the 
mouth.  Various  constitutional  diseases,  by  lowering  vital 
resistance  are  predisposing  factors.  At  first  the  lesion  is 
confined  to  the  gum  tissue  (gingivitis),  giving  rise  to  no 
roentgenographic  changes.  Later,  the  peridental  mem- 
brane is  attacked  (chronic  gingivopericementitis),  the  in- 
fection progressing  slowly  from  the  gum  margin  toward 
the  apex  of  the  tooth.  In  the  roentgenogram  at  this  stage 
we  may  see  a  thickening  of  the  normal  peridental  dark 
line.  Very  soon  after  involvement  of  the  pericementum, 
the  bone  becomes  affected  (osteopericementitis),this  being 
first  manifested  in  the  odontogram  by  absence  of  the  apex 
of  the  bony  septum  between  the  teeth.  The  bone  surround- 
ing the  tooth  is  now  progressively  destroyed  toward  the 
apex,  and  the  entire  bony  support  of  the  tooth  may  be  lost. 
Sometimes  sufficient  bone  remains  in  the  apical  region  to 
give  the  tooth  a  good  deal  of  firmness,  and  it  is  surprising- 
how  little  bone  ma}'  be  indicated  in  the  odontogram  for 
this  to  be  the  case.  In  the  roentgenogram  the  loss  of 
bone  is  shown  by  a  lessening  in  density  which  in  advanced 
cases  may  completely  surround  the  tooth.  As  the  bony 
support  is  destroyed,  the  tooth  may  incline  from  its  nor- 
mal axis,  particularly  if  an  adjoining  tooth  has  been  lost. 


48  INTERPRETATION    OF    ROENTGENOGRAMS 

Deposits  of  calculus  upon  the  root  and  absorption  and 
irregularities  of  the  cementum  are  also  shown.  In  molar 
teeth,  chronic  suppurative  pericementitis  may  be  shown 
in  the  odontogram  as  a  dark  area  of  absorption  at  the  bi- 
furcation of  the  roots. 

Roentgenographic  study  of  cases  of  chronic  suppura- 
tive pericementitis  is  of  importance  in  order  to  determine 
the  extent  of  bone  destruction  in  deciding  the  line  of 
treatment  to  be  followed.  It  is  also  of  value  in  showing 
new  bone  formation  in  the  course  of  treatment  of  a  case. 


CHAPTER  IV 

CORRELATION    OF    CLINICAL    FINDINGS    WITH 
ROENTGENOGRAPHIC  EXAMINATION 

Errors  in  diagnosis  of  tooth  conditions  are  frequently 
observed  owing  to  lack  of  coordination  of  the  clinical, 
roentgenologic,  and  other  parts  of  the  examination.  The 
roentgen  examination  is  frequently  made  and  the  findings 
reported  independently  of  or  entirely  without  a  clinical 
examination  of  the  mouth,  and  vice  versa.  On  account 
of  this,  important  pathologic  conditions  are  sometimes 
overlooked ;  or,  on  the  other  hand,  undue  significance  may 
be  attached  to  the  findings  of  either  examination. 

False  interpretation  of  dental  films  by  roentgenologists 
is  not  infrequent.  On  the  other  hand,  cases  are  often  seen 
in  which  clinical  examination  alone,  without  the  roentgen 
ray,  failed  to  reveal  serious  lesions  that  were  present. 

In  order  that  these  errors  ma^^  be  avoided  as  far  as  pos- 
sible, a  definite  routine  should  be  followed  preliminary 
to  making  the  roentgen  examination,  particularly  where 
a  complete  examination  of  the  teeth  and  surrounding- 
parts  is  desired,  in  the  detection  of  any  possible  foci  of 
mouth  infection. 

Routine  Examination 

First  of  all,  the  person  upon  whom  the  interpretation 
of  the  roentgenograms  devolves,  should  know  as  much  as 
possible  of  the  history  of  individual  teeth  of  the  patient, 
in  regard  to  previous  treatment,  abscesses,  swellings, 
pain,  etc.  A  knowledge  of  particulars  of  this  kind  may 
vitally  modify  the  interpretation. 

A  general  survey  of  the  mouth  and  associated  parts 
should  be  made.     In  this  way  \\w  cxainiuci-  (^])tains  a 

49 


50  INTEEPEETATION    OF    ROENTGENOGRAMS 

clue  as  to  the  nature  and  extent  of  the  roentgenologic  ex- 
amination required.  The  presence  of  pyorrhea,  ulcera- 
tions, suppurating  sinuses,  swellings,  etc.,  is  noted. 

Electric  Test. — The  next  important  step  consists  in 
determining  and  noting  down  on  a  chart,  so  far  as  pos- 
sible the  condition  of  each  tooth  in  regard  to  vitality  of 
the  pulp,  which  teeth  are  crowned,  and  which  are  miss- 
ing. The  most  convenient  and  reliable  method  of  deter- 
mining pulp  vitality  is  by  means  of  the  faradic  battery, 
shown  in  Fig.  21.  This  batter}^  contains  one  dry  cell. 
The  negative  electrode  is  held  in  the  hand  of  the  patient. 


Fig.    21. — Faradic    battery    used    to    test    pulp    vitality. 

The  positive  pole  consists  of  a  pointed  dental  exploring 
instrument  mounted  on  an  insulated  handle.  The  point 
is  wrapped  with  a  wisp  of  cotton  and  dipped  in  water. 
Starting  at  the  median  line  of  the  upper  jaw,  each  tooth 
presenting  an  enamel  surface  is  touched  in  turn  with  the 
moistened  electrode,  and  the  result  noted  as  minus,  plus 
or  doubtful.  Crowned  teeth  are  marked  ''C, "  and  miss- 
ing teeth  ''M."  This  chart  then  forms  the  basis  for  the 
roentgen  examination,  which  is  to  be  applied  to  all  places 
in  the  mouth  showing  negatively  responding,  crowned, 
or  missing  teeth.    The  teeth  with  vital  pulps  can  usually 


CORRELATIOlSr    OF    CLINICAL   FliSTDIXGS  51 

be  ignored,  as  tliey  are  practicalh^  never  the  seat  of  hid- 
den apical  disease.  Of  course,  it  may  frequently  be  nec- 
essary to  subject  teeth  with  vital  pulps  to  roentgen  ex- 
amination to  show  the  amount  of  bone  destruction  due  to 
pyorrhea.  The  faradic  test  is  not  absolutely  infallible  in 
determining  the  vitality  of  the  pulp,  but  it  is  the  best 
means  that  we  have  at  present.  A  false  negative  result 
may  be  obtained  sometimes  in  teeth  with  recession  of  the 
pulp  and  formation  of  secondary  dentine,  while  a  false 
positive  response  may  be  due  to  the  presence  of  large 
metallic  fillings  conveying  the  current  to  the  gum  or  to 
contiguous  vital  pulps.  For  this  reason  also,  the  current 
is  not  relia])le  in  determining  the  vitality  of  pulps  be- 
neath shell  crowns.  In  such  cases  it  may  be  necessary  to 
remove  the  crown  and  then  apply  the  test.  A  nervous 
patient,  too,  may  imagine  he  feels  a  response  in  a  pulpless 
tooth  after  receiving  several  shocks  in  succession  through 
vital  pulps. 

The  foregoing  steps  in  the  mouth  examination  are  to 
be  regarded  as  preliminary  or  leading  up  to  the  roentgeno- 
graphic  examination.  Without  them  as  a  guide  we  should 
be  forced  either  to  pick  out  certain  suspected  areas  for 
roentgenographic  study,  thus  many  times  overlooking 
far  more  important  conditions,  or,  as  is  done  by  many 
roentgenologists,  make  films  showing  ever}^  tooth  in  the 
mouth,  which  is  obviously  a  waste  of  time  and  material, 
and  also  frequently  incomplete. 

We  endeavor  to  overcome  the  defects  of  the  usual 
methods  of  examination  by  the  following  plan: 

First  of  all  a  plate  (5x7  inches)  is  made  of  each  side, 
taking  in  all  the  teeth  of  the  upper  and  lower  jaws  from 
the  canines  backward,  and  also  shoAving  the  region  of  the 
angle  and  ramus.  This  gives  a  general  survey  of  the 
mouth,  discounting  any  preconceived  ideas  as  to  condi- 
tions expected  to  be  found.  Unsuspected  abnormalities 
are  in  this  way  frequently  discovered,  Avhich  would  be 


52  INTERPRET ATIOi!^    OF    ROEiSTTGEISTOGRAMS  . 

overlooked  if  only  certain  areas  or  even  the  usual  loca- 
tions of  teeth  were  covered  with  films ;  in  addition  to  this, 
pathologic  conditions  about  lower  premolars  and  molars 
are  generally  more  satisfactorily  shown  in  plates  than  in 
films.  Omng  to  trismus,  it  ma}^  he  impossible  to  place  a 
film  mthin  the  mouth.  After  exposing  the  plates,  each 
smgle  area  comprising  teeth  either  crowned  or  negative 
to  the  electric  current,  or  considered  to  require  more  de- 
tailed study  than  is  shown  in  the  plate,  and  any  area  in 
the  front  part  of  either  jaw  from  which  teeth  are  missing, 
is  covered  Avith  a  small  film.  The  film  picture  shows  the 
opposite  aspect  of  that  which  is  shown  in  the  plate,  this 
being  due  to  the  fact  that  the  plate  is  extraoral,  and  the 
film  intraoral. 

B}^  following  this  routine,  we  have  been  rewarded  man}- 
times  by  the  detection  of  unerupted  teeth,  especially  third 
molars,  cysts,  odontomas,  roots  in  the  maxillary  sinus, 
diseased  maxillary  sinuses,  etc.,  which  might  easily  have 
been  overlooked  had  films  been  depended  upon  alone.  One 
of  the  fundamental  princi]3les  of  a  general  physical  exam- 
ination is  the  importance  of  surve3^ing  the  body  as  a 
whole.  In  the  same  way,  in  this  special  field,  we  should 
examine  the  entire  mouth,  not  blindly,  but  in  an  intel- 
ligent manner,  instead  of  selecting  suspected  areas  here 
and  there  with  films.  Of  course,  as  a  guide  in  the  treat- 
ment of  individual  teeth,  a  film  exposure  usually  is 
sufficient. 

Record  of  Examii^ation" 

Fig.  22  shows  the  record  of  a  specimen  case.  At  the 
top  is  a  chart  of  the  teeth,  with  the  results  of  the  f  aradic 
test;  crowned  and  missing  teeth  are  also  marked.  Below 
are  shown  the  plates  of  the  two  sides,  with  films  covering 
the  pulpless  and  crowned  teeth  in  the  upper  jaw.  For 
the  lower  teeth  the  plates  alone  usually  are  sufficient.  In 
this  case  our  interpretation  should  read  about  as  follows : 

Upper    Right. — Central    incisor    crowned,    imperfect 


COREELATION"    OF    CLI]SriCAL    FIJiTDIl^GS  53 

root  filling-,  periapical  rarefying  osteitis  with  suppura- 
tion, and  absorption  of  root;  there  is  also  a  perforation  of 
side  of  root;  first  premolar,  devitalized  pulp,  no  root  fill- 
ing, periapical  rarefying  osteitis  with  granuloma;  this 
area  extends  to  the  periapical  region  of  the  second  pre- 
molar, previously  extracted;  first  and  second  molars  pulp- 
less,  partial  root  fillings,  periapical  regions  normal. 

Upper  Left. — Central  incisor  crowned,  partial  root 
filling,  small  area  of  periapical  rarefying  osteitis  with 
granuloma ;  lateral  incisor  pulpless,  good  root  filling,  peri- 
dental thickening  about  apex;  canine  pulpless,  good  root 
filling,  apex  normal;  first  premolar  crowned,  imperfect 
root  fillings,  slight  peridental  thickening  about  apices; 
second  premolar  crowned,  partial  root  filling,  small  area 
of  periapical  rarefying  osteitis  with  granuloma;  first 
molar  has  been  jDreviously  extracted,  and  at  this  point  is 
a  large  area  of  bone  destruction,  probably  with  cyst 
formation. 

Lower  Right. — Second  premolar  pulpless,  partial  root 
filling,  periapical  region  normal ;  second  and  third  molars 
crowned,  partial  root  fillings,  periapical  rarefying  oste- 
itis, probably  with  granulomas,  about  the  teeth. 

Lower  Left. — Second  molar  crowned,  partial  root  fill- 
ings, periapical  region  apparently  normal;  the  croA^^l 
on  this  tooth  has  an  overhanging  edge,  permitting  the 
collection  of  food  and  debris. 

Positions  Used  in  Exposixg  Plates  axd  Films 

While  this  book  is  primarily  intended  to  throw  light 
on  the  interpretation  of  dental  and  maxillary  roentgeno- 
grams, it  is  not  considered  out  of  place  to  briefly  describe 
the  positions  used  by  the  writer  in  exposing  the  plates 
and  films. 

Most  operators  in  making  roentgenograms  of  the  head 
and  teeth  place  the  patient  in  the  recumbent  position, 
which  entails  considerable  preparation  and  discomfort. 


54 


INTERPEETATIO]Sr    OF    ROENTGENOGRAMS 


According  to  the  following  technic  the  work  is  done  with 
the  patient  in  a  sitting  posture  on  a  chair  facing  the 
stand.    A  stand  of  a  well-known  make  is  employed.    To 


r-A   -     C    I' 


c  c 


amOOOJUUmO/JDoa 


"^f" 


RQRQl^mW 


■*  J  LV  JV  V 


C     C     />^—  -r+--r+  "^-^  -5-  -V-  4-   H    C      N\ 


Fig.   22-A. 


Fig.  22-B. 


/I. — Diagram   of   teeth,   with   faradic   reaction,    etc.,    indicated. 
B.— Plate   of  left   side. 

it  is  added  a  standard  head  clamp,   and  a  plate  rest 
specially  designed  by  the  late  Dr.  E.   J.  Eisen.     The 


CORRELATION    OF    CLINICAL    FINDINGS 


55 


Fig.   22.-C. 


Fig.   22-D. 


Fig.  22-E. 


Fig.  22-R 


Fig.  22. 


Fig.  22-G. 


C— Plate  of  right  side.  ^  D  and  B. — Films   of   upper  left  teelh. 

F  and   G. — Films   of   upper  right  teeth. 


56 


INTERPRET ATIOlsr    OF    ROENTGENOGRAMS 


plate  rest  is  fixed  at  an  angle  of  15  degrees  do\\Tiward 
from  the  horizontal,  and  is  placed  19  inches  from  the 
target.  The  tube  holder  and  funnel  are  drawn  out  to  the 
full  length  of  the  horizontal  arm  of  the  stand,  and  tipped 
inwardly  at  an  angle  of  30  degrees  from  the  vertical  (Fig. 
23).  A  5x7  inch  plate  with  the  emulsion  side  up  is  placed 
on  the  plate  rest.  The  patient  is  now  seated  somewhat  to 
the  right  or  left  of  the  stand  with  the  head  laid  on  the 


Fig.   23. — Eisen   plate   rest   attached   to   stand   for   taking   head   plates. 


plate  in  such  a  position  that  the  focal  ray  will  pass 
through  the  mastoid  process  of  the  uppermost  side  of  the 
head  (Fig.  24).  This  position  brings  the  uppermost  side 
of  the  mandible  in  as  nearly  a  perpendicular  position  as 
possible  to  the  plate,  thus  minimizing  overlapping  of  the 
two  sides.  If  canine  and  premolar  regions  are  particu- 
larly desired,  the  patient's  nose  should  be  pressed  against 
the  plate,  while  for  molars  the  nose  should  be  slightly 


CORRELATION    OF    CLIXICAL    FI]S'DINGS 


57 


raised  from  the  plate.    The  head  clamp  is  now  tightened, 
and  the  exposure  made. 

For  intraoral  films,  the  angle  of  the  tube  holder  is  re- 
versed as  shown  in  Fig.  25,  the  patient's  head  being  sup- 
ported by  an  ordinary  head  rest  attached  to  the  back  of 
the  chair.  As  a  rule,  no  sort  of  film  holder  other  than  the 
patient's  thumb  or  finger  is  necessary,  though  occasion- 
ally the  cork  devised  by  Dr.  M.  L.  Rhein  is  of  advantage. 
The  film  fits  into  a  slot  cut  in  the  cork  and  bv  this  means 


Fig.   24. — Position  of  head   and   angle  for  left  side   of  jaws. 

is  held  between  the  patient's  teeth.  The  emulsion  side 
of  the  film  is  always  placed  against  the  teeth  to  be  taken. 
Modifications  of  these  routine  positions  must,  of  course, 
be  made  to  suit  individual  cases.  Where  symptoms  sug- 
gest the  possibility  of  disease  of  the  nasal  accessory 
sinuses,  or  where  it  is  suspected  that  dental  infection  in- 
volves the  maxillary  sinus,  roentgenographic  examina- 
tion of  these  parts  is  often  of  value.  This  is  carried  out 
by  using  the  technic  described  by  "Waters  and  Waldron 
(American  Journal  of  Roenfgenologi/,  February,  1915), 


00  II^TERPEETATIOiSr    OF    ROENTGEjSTOGEAMS 

for  which  this  stand  is  well  adapted.  An  8x10  inch 
plate  is  used,  at  22  inches  from  the  target.  The  patient  is 
seated  directly  in  front  of  the  stand, — if  a  woman,  with 
all  hairpins  removed — and  the  head  placed  on  the  ]3late 
rest  with  the  chin  touching  the  plate  and  the  nose  not 
quite  touching.  The  tube  holder  is  tipped  until  the  base 
of  the  funnel  is  parallel  with  the  plate,  and  the  focal  ray 
directed  toward  the  root  of  the  nose.     (Fig.  26.)     By 


Fig.  25. — Position    for   exposing    intraoral    dental   films. 

means  of  a  plate  of  this  kind  the  two  sides  of  the  face  can 
be  compared  and  empyema  of  the  antrum  of  Highmore 
or  of  the  other  sinuses  detected  by  increased  opacity  to 
the  rays  as  compared  with  the  healthy  side.  It  is  seldom 
possible  from  a  plate  or  film  showing  conditions  only  on 
one  side  to  detect  the  presence  of  pus  in  the  antrum,  but 
by  the  addition  of  the  sinus  plate  just  described,  the  diag- 
nosis may  often  be  completed.    Fig.  27  shows  opacity  of 


COREELATIOiSr    OF    CLIjSTICAL    FINDINGS 


59 


tlie  left  maxillary  sinus,  due  to  empyema.  Still  further 
information  may  be  obtained  when  necessary  by  making- 
lateral  or  vertical  views  of  the  sinuses. 

Identification  of  Given  Plates  and  Films  with  the  Sides 
and  Parts  of  the  Mouth  to  Which  They  Belong 

Provided  that  plates   and  films  have  been  made   ac- 
cording to  the  technic  described,  how  is  one  who  has  not 


Fig.   26. — Diagram    showing    position    for    exposing    sinus    plate,    and    projection    of 
tlie  sinuses  on  the  plate. 

witnessed  the  examination  to  determine  which  teeth  are 
depicted  in  a  given  plate  or  film? 

Plates. — In  exposing  a  plate,  it  is  recalled  that  the 
side  of  the  face  to  be  slioAvn  is  laid  against  the  emulsion 


60  IjSTTEEPPvETATIOX    of    EOENTGEiSrOGPiAMS 

surface  and  the  rays  directed  from  the  opposite  side  of  the 
head.  Therefore,  a  finished  plate  of  the  riglit  side,  with 
the  emulsion  surface  toward  the  observer,  should  look 
toward  the  left,  while  a  plate  of  the  Jeff  side  should  look 
toward  the  right. 

Films. — In  making  a  film,  it  is  placed  in  the  mouth 
with  the  emulsion  surface  toward  the  inner  or  lingual 
aspect  of  the  teeth,  and  the  rays  directed  from  the  same 
side  of  the  head.    A  finished  film  should  be  viewed  with 


Fig.    27. — Opacity   due   to    empyema    of   left   maxillary   sinus. 

the  shiny  surface  toward  the  observer.  In  the  case  of 
the  anterior  teeth,  the  uppers  and  lowers  are  distin- 
guished by  their  size  and  shape.  The  teeth  on  the  right 
side  will  be  to  the  right  of  the  film,  and  the  left  to  the 
left.  Films  of  upper  posterior  teeth  are  frequently  dis- 
tinguished by  showing  outlines  of  the  maxillary  sinus, 
while  in  lower  films,  the  occlusal  line  of  the  teeth  is 
generally  concave,  and  the  mandibular  canal  and  mental 
foramen  may  be  slioA\m.    The  upper  and  lower  molars  are 


CORRELATION    OF    CLINICAL   FUsTDINGS  61 

also  disting'nislied  by  the  number  of  their  roots.  With 
an  upper  fihn  held  with  the  roots  of  the  teeth  pointing- 
upward,  and  a  lower  film  with  the  roots  pointing  down, 
shin}^  side  of  film  toward  the  observer,  the  hindermost 
teeth  of  a  film  of  the  right  side  will  be  toward  the  riglit 
of  the  film,  and  the  hindermost  teeth  of  a  film  of  the  left 
side  will  be  to  the  left  of  the  film.  This  explanation  is 
difficult  to  give  in  words,  but  after  a  little  practice  the 
recognition  of  the  part  of  the  mouth  to  which  a  film  be- 
longs becomes  automatic.  In  the  illustrations  shown 
throughout  the  book,  the  rules  just  given  have  been 
followed. 


CHAPTER  V 

ROENTGENOGEAPHIC     FINDINGS     ABOUT     THE 

TEETH  AND  JAWS  IN  THEIR  RELATION 

TO  PROGNOSIS  AND  TREATMENT 

The  physician  is  frequently  called  upon  to  decide  or 
give  advice  on  the  question  of  saving  or  removing  teeth 
which  have  caused  or  are  associated  with  given  patho- 
logic conditions  as  revealed  by  the  roentgen  ray.  While 
each  case  must  be  considered  individually,  yet  it  is  pos- 
sible to  lay  down  certain  rules  for  general  guidance. 
Like  all  generalities,  they  are  subject  to  exceptions  and 
modifications. 

The  diagnosis  of  periapical  pathologic  conditions  about 
the  teeth  depends  upon  the  history,  the  symptoms,  the 
clinical  examination,  and  the  roentgen  examination. 
AVhen  these  have  resulted  in  a  diagnosis,  one  of  three 
methods  of  treatment  so  far  as  the  tooth  is  concerned,  is 
to  be  considered;  namely,  (1)  conservative  treatment; 
(2)  surgical  removal  of  the  diseased  condition  by  resec- 
tion of  the  root  with  curettement  of  the  diseased  bone 
area;  and  (3)  extraction  of  the  tooth  followed  by  curette- 
ment of  the  diseased  bone  area. 

Many  times  teeth  are  condemned  for  extraction  which 
could  be  safely  retained  by  proper  treatment,  owing  to 
lack  of  discrimination  on  the  part  of  the  physician. 

On  the  other  hand,  the  training  of  the  average  dentist 
does  not  permit  him  to  grasp  the  broad  pathologic  aspect 
of  the  question,  with  the  result  that  he  may  often  attempt 
conservation  of  teeth  which  may  be  a  danger  to  the  life 
of  the  patient,  and  labor  under  the  mistaken  belief  that 

62 


PEOGNOSTS    AND    TREATMENT  63 

he  lias  by  inadequate  treatment  freed  teeth  from  infec- 
tion when  in  reality  the}^  still  remain  a  menace. 

Until  dentists  become  more  familiar  with  diseased  con- 
ditions of  the  body  in  general,  the  responsibility  in  this 
matter  in  jiatients  suffering-  from  systemic  infection  w^ith 
foci  in  the  mouth  should  lie  with  the  physician,  and  this 
necessarily  requires  on  his  part  a  familiarity  with  roent- 
genographic  interpretation  of  these  dental  conditions.  In 
the  formation  of  an  opinion  as  to  whether  conservative  or 
operative  treatment  should  be  carried  out,  the  question 
of  the  training  of  the  dentist  for  this  particular  work 
must  be  considered.  Unless  the  dentist  is  familiar  with 
modern  methods  of  aseptic  root  canal  work,  and  is  guided 
and  checked  in  his  operations  by  the  roentgen  ray,  by  far 
the  safest  procedure  is  the  immediate  extraction  of  any 
tooth  in  which  the  pulp  chamber  is  entered  by  decay, 
whether  or  not  periapical  infection  be  demonstrated.  If 
the  patient  is  in  the  hands  of  a  competent  dentist,  with 
a  sense  of  surgical  asepsis,  and  familiar  with  modern 
accessories  that  have  been  found  by  the  best  workers  to 
be  essential,  much  can  be  accomplished  in  the  saving  of 
many  teeth  that  show  distinct  evidence  of  extension  of 
infection  to  the  periapical  region. 

The  question  of  conservative  or  radical  treatment  of 
teeth  showing  periapical  involvement  should  first  of  all 
be  decided  by  the  general  health  of  the  patient.  Our  at- 
titude toward  treatment  of  suspected  diseased  teeth  in 
patients  who  have  some  systemic  condition  in  which 
mouth  infection  is  possibly  playing  a  part  should  be 
much  more  radical  than  that  adopted  in  patients  having 
no  physical  ailments.  Many  times  a  tooth  may  be  passed 
along  for  treatment  in  a  healthy  individual  where  in  an 
invalid  a  tooth  so  affected  would  be  removed  without 
hesitation.  So  far,  no  reliable  or  satisfactory  preopera- 
tive pathologic  means  of  proving  the  connection  between 
suspected  peridental  areas  and  systemic  conditions  has 


64  INTERPEETATIOlSr    OF    EOElSrTGEjSrOGEAMS 

been  discovered,  so  at  present  we  must  take  the  risk  of 
occasionally  sacrificing-  a  harmless  tooth,  which  is  a  small 
matter  when  weighed  in  the  balance  against  the  general 
health  of  the  individual. 

Periapically  diseased  teeth,  as  shown  b}^  the  roentgen 
ray  and  other  means  of  examination  fall  into  two  general 
groups  so  far  as  treatment  is  concerned:  (1)  those  which 
should  unquestionably  be  extracted  under  all  conditions, 
and  (2)  those  in  which  more  conservative  treatment  may 
be  attempted. 

1.  In  the  first  group  fall  teeth  showing  the  following 
conditions : 

(A)  Large  periapical  areas  of  chronic  rarefying  oste- 
itis in  which  one-third  or  more  of  the  peridental  mem- 
brane has  been  lost  and  in  which  the  cementum  is  eroded 
and  absorbed. 

(B)  Teeth  in  which  the  side  of  the  root  has  been  per- 
forated and  infection  of  the  lateral  peridental  membrane 
with  bone  destruction  has  occurred. 

(G)  All  upper  molars  and  all  lower  teeth  with  extensive 
IDeriapical  areas  of  chronic  rarefying  osteitis  with  granu- 
loma, suppuration,  or  cyst  formation,  or  even  compara- 
tively small  areas  in  which  the  x-ray  reveals  root  rough- 
ening or  absorption,  because  the  locations  of  these  teeth 
are  not  as  a  rule  favorable  for  root  resection. 

Teeth  falling  in  Classes  A,  B,  and  C  should  be  unhesi- 
tatingly extracted  regardless  of  whether  tlie  patient  is 
otherwise  healthy  or  not. 

2.  In  the  second  group  are  found  teeth  in  which  in 
otherwise  healthy  individuals  an  effort  at  conservation 
may  be  attempted  by  measures  directed  toward  opening, 
draining,  and  sterilizing  root  canals  and  periapical  areas, 
followed  by  root  canal  filling,  and  in  some  cases  finally 
completed  by  root  resection.  Such  teeth,  with  appro- 
priate treatment  indicated,  may  be  classified  as  follows : 

(D)   Teeth  showing  peridental  thickening  in  the  apical 


PROGNOSIS    AND    TREATMENT  65 

region,  due  to  chronic  jDroliferative  pericementitis  may 
be  treated  by  opening,  draining,  sterilizing,  and  filling 
root  canals  after  negative  culture,  followed  by  periodical 
roentgen  examinations. 

(E)  Teeth  showing  small  areas  of  periapical  bone  de- 
struction with  granuloma  may  be  treated  as  in  Class  D, 
followed  by  apical  root  resection  and  curettement,  in  the 
case  of  upper  incisors,  canines,  and  premolars,  and  extrac- 
tion when  located  in  other  parts  of  the  mouth,  if  examina- 
tion three  months  later  shows  no  reduction  or  oblitera- 
tion of  periapical  area, 

(F)  Upper  incisors,  canines,  and  premolars,  with  larger 
periapical  areas  of  granuloma,  suppuration  or  cyst  for- 
mation, with  or  without  roughening  and  absorption  of 
apical  cementum,  and  even  smaller  areas  associated  with 
the  latter  condition  should  be  treated  by  the  usual  root 
canal  opening,  sterilization,  and  filling,  and  immediate 
apical  root  resection  and  curettement  followed  by  extrac- 
tion if  at  the  end  of  three  months  the  x-ray  reveals  no 
attempt  at  bone  regeneration  in  the  area  involved. 

Teeth  falling  in  Classes  E  and  F,  and  occasionally  also 
in  Class  D  should  be  extracted  without  attempts  at  con- 
servative treatment  in  cases  in  which  they  are  believed 
to  be  the  cause  of  systemic  infection. 

Chronic  Suppurative  Pericementitis  or  Pyorrhea 

As  regards  the  treatment  of  teeth  involved  in  this  con- 
dition, the  following  general  rules  may  be  followed: 

Teeth  where  the  surrounding  bone  destruction  is  so 
great  as  to  deprive  the  tooth  of  over  one-third  of  its  sup- 
port, should  be  extracted. 

Multirooted  teeth  in  which  the  bone  destruction  and 
granulation  tissue  have  extended  to  the  bifurcation  of  the 
roots,  should  be  extracted. 

Teeth  in  which  suppuration  from  pyorrheal  pockets 


66  INTERPRETATION    OF   ROENTGENOGRAMS 

resists  persistent  attempts  at  conservative  treatment  or 
treatment  by  gum  amputation,  should  be  extracted. 

It  is  felt  that  physicians  advising  and  dental  surgeons 
carrying  out  treatment  in  accordance  with  the  general 
rules  outlined  above,  in  the  majority  of  cases,  will  be 
open  to  criticism  neither  for  iiltraconservatism  on  the  one 
hand,  nor  for  undue  radicalism  on  the  other,  but  will  be 
following  a  sane  middle  course. 


CHAPTER  VI 

STEREOSCOPIC  AND  OTHER  METHODS  OF 
LOCALIZATION 

Roentgenograms,  as  ordinarily  made,  are  flat  pictures; 
i.  e.,  they  do  not  give  any  perspective,  and  it  is  impos- 
sible in  such  a  picture  to  determine  the  relative  joositions 
of  given  parts  except  in  two  dimensions.  In  the  majority 
of  dental  conditions  in  which  the  roentgen  ray  is  an  aid  in 
diagnosis,  the  simple  flat  odontograms  give  all  necessary 
information;  but  occasionally  one  meets  with  a  case  in 
which  other  methods  are  called  into  use  with  advantage. 
In  the  case  of  an  unerupted  canine,  for  instance,  it  is  im- 
possible to  determine  from  a  single  film  whether  the  un- 
erupted tooth  lies  on  the  labial  or  the  palatal  aspect  of 
the  other  teeth,  and  clinical  signs  of  its  position  are  often 
lacking. 

We  have  two  means  of  gaining  a  more  accurate  knowl- 
edge of  the  relative  positions  of  different  objects  in  the 
roentgenogram:  (1)  stereoscopic  method;  (2)  by  making- 
two  or  more  odontograms  in  different  positions,  and  com- 
paring the  several  pictures. 

Stereoroentgenography 

In  the  case  of  an  unerupted  impacted  tooth,  a  foreign 
body,  or  a  fracture,  the  information  obtained  from  a 
stereoscopic  view  is  often  of  inestimable  value,  tlie 
method  yielding  as  it  does  a  picture  of  almost  equal  clear- 
ness and  perspective  as  would  be  obtained  by  actual 
visual  examination  through  the  hard  tissues  involved. 

In  making  stereograms  of  the  teeth  and  jaws  either 
plates  or  films  are  employed,  according  to  the  location 

67 


bo  IlSTTEEPEETATIOl^J"    OF    EOEITTGEl^rOGEAMS 

and  extent  of  the  area  involved.  For  showing  conditions 
about  individual  teeth,  especially  in  the  front  of  the 
mouth,  films  may  be  used,  while  plates  are' more  suitable 
in  cases  involving  the  posterior  part  of  the  mouth,  such 


Fig.   28. — Position  and  angle  of  tube  for  first  exposure  in  plate  stereogram  of  the  jaws. 


Fig.   29. — Diagram   giving   the   angles    of   the   tube   in   making   stereograms    of   the  jaws 

and   teeth. 

as  impacted  third  molars,  or  where  a  considerable  area  is 
to  be  examined,  as  in  the  case  of  fractures,  embedded 
bullets,  etc. 

Technic 

The  technic  of  plate  stereograms  will  be  described  first. 
The  operation  involves  making  tAvo  exposures  Avith  the 


METHODS    OF    LOCALIZATION 


69 


tube  in  different  positions.  The  first  exposure  is  made 
with  the  same  position  of  tube  and  patient  as  for  a  single 
plate  described  on  p.  56.  (Figs.  28  and  29-A.)  The 
patient  is  instructed  to  keep  the  head  in  exactly  the  same 
position  for  the  two  exposures,  as  any  movement  will 
interfere  with  the  stereoscopic  effect.  Care  must  also 
be  taken  to  place  the  second  plate  in  exactly  the  same  posi- 
tion as  the  first,  which  is  easily  accomplished  by  means 


Fig.   30. — Position   and   angle   of  tube   for   second   e.xposure   in   plate   stereogram   of   the 

jaws. 


of  lines  ruled  on  the  plate  rest  or  by  means  of  a  special 
slot  arrangement  in  the  plate  rest  into  which  the  plates 
can  be  slipped.  The  first  plate  having  been  slid  out  from 
under  the  patient's  head  and  the  second  plate  placed  in 
the  same  position,  the  tube  is  shifted  three  inches  in  to- 
ward the  upright  stand.  In  order  for  the  central  ray  to 
strike  the  second  plate  at  the  same  point  as  in  the  first, 
it  becomes  necessary  to  change  the  aneie  of  the  funnel 


70  INTERPRETATION^    OF    ROENTGENOGRAMS 

from  30  degrees  to  17^  degrees  from  the  vertical  (Figs. 

30  and  29-B).  The  second  exposure  is  now  made,  exactly 
the  same  time  being  given  as  in  the  first  exposure.  After 
development,  the  plates  may,  of  course,  be  vieAved  through 
the  large  Wheatstone  stereoscope.  If  this  instrument  is 
not  available,  lantern  slides  or  prints  can  be  made  from 
corresponding  parts  of  the  two  plates,  and  viewed  very 
satisfactorily  through  the  ordinary  hand  stereoscope.  In 
viewing  these  plates  through  the  stereoscope,  it  must  be 
remembered  that  they  must  be  placed  sideways,  owing 
to  the  direction  in  which  the  tube  Avas  shifted  between 
the  exposures. 

In  mounting  the  lantern  slides  for  the  stereoscope  a 
cover-glass  is  made  by  washing  the  emulsion  off  an  old 
5x7  inch  plate,  cutting  it  down  to  4x7  inch,  and  fastening 
the  slides  to  this  with  paper  or  cloth  binding  strips.    Fig. 

31  illustrates  the  value  of  stereoscopic  roentgenography 
in  locating  an  unerupted  impacted  upper  third  molar. 
There  were  no  signs  to  indicate  the  position  of  this  tooth 
by  ordinary  examination.  Ordinarily  such  a  tooth  would 
be  assumed  to  lie  disto-huccally  in  relation  to  the  second 
molar,  and  a  single  x-ray  plate  would  only  confirm  this 
assumption.  Stereoscopic  plates,  however,  showed  that 
the  third  molar  lay  on  the  disto-palatal  aspect  of  the 
second  molar.  The  operative  incision  was  made  at  this 
point,  the  tooth  readily  found,  and  laceration  of  the  buccal 
side  of  the  gum  was  avoided. 

In  making  intraoral  films  stereoscopically,  the  most  im- 
portant points  to  be  observed  are  that  the  patient's  head 
and  the  film  must  maintain  the  same  position  for  the  two 
exposures.  The  angles  for  the  tube  holder  are  based  on 
a  working  distance  of  sixteen  inches  from  target  to  film. 
The  plate  rest  is  first  removed  from  the  stand.  The  tube 
holder  is  then  tipped  sidewise  at  an  angle  to  suit  the  indi- 
vidual case  in  the  plane  at  right  angles  to  the  dental  arch 
of  the  patient.    In  the  plane  parallel  to  the  dental  arch. 


METHODS    OF    LOCALIZATION 


71 


i  o 

MS 

C.2 


H^ 


■>'o 


72  INTEEPEETATION    OF    ROENTGENOGRAMS 

the  funnel  is  in  a  vertical  position.  (Fig.  32.)  The  pa- 
tient is  now  seated  in  the  chair,  with  the  head  supported 
by  the  head  rest  in  such  a  position  from  the  end  of  the 
funnel  that  with  the  film  in  the  mouth  against  the  teeth  to 
be  studied  there  will  be  approximately  a  distance  of  six- 
teen inches  from  target  to  film.  The  position  should  also 
be  adjusted  to  avoid  distortion  as  much  as  possible.  This 
' '  centering ' '  having  been  accomplished,  the  tube  is  placed 
in  position  for  the  first  exposure  by  moving  it  one  and  one- 
half  inches  to  the  left  of  the  central  point,  and  tipping  it 
inward  at  an  angle  of  7%  degrees  from  the  vertical  plane. 
This  will  bring  the  focal  ray  to  the  same  spot  on  the  film 
as  with  the  tube  in  the  central  position  (Figs.  33  and 
29-Z)).  After  the  first  exposure  has  been  made,  the  second 
film  is  quickly  inserted  in  the  same  position  in  the  mouth 
as  the  first,  care  being  taken  not  to  move  the  patient 's 
head.  The  tube  is  now  shifted  three  inches  to  the  right 
and  tipped  at  an  angle  of  7^  degrees  from  the  vertical 
in  the  opposite  direction  from  that  of  the  first  exposure, 
so  that  the  central  ray  will  again  converge  at  the  same 
spot  on  the  film  (Figs.  34  and  29-C). 

In  viewing  films  through  the  stereoscope  the  difficulty 
in  mounting  them  so  that  identical  objects  in  the  two 
films  will  fuse  readily  is  overcome  by  the  following  plan : 
a  piece  of  glass  is  cut  from  an  old  5x7  inch  plate  to  a 
suitable  size  to  fit  the  stereoscope  •(4x7  inches).  To  this 
are  applied  pieces  of  paper  binding  strip  which  have  been 
previously  folded  longitudinally  so  that  only  about  one- 
third  of  the  original  width  of  the  gummed  side  is  exposed. 
In  this  manner  two  slots  are  formed  into  which  the  films 
will  fit  at  approximately  the  proper  distance  apart.  The 
films  are  thus  not  mounted  in  absolutely  fixed  positions, 
but  can  be  slid  up  and  down  and  even  slightly  obliquely, 
so  that  they  can  be  readily  adjusted  to  such  positions  that 
the  two  images  will  merge  when  focused  (Fig.  35).  Fig. 
36  is  a  view  of  the  ordinary  hand  stereoscope.    It  is  not 


METHODS    OF    LOCALIZATION 


73 


Fig.   32. — Central  position  of  the  tube  prior  to  making  stereoscopic  film  exposures. 


Fig.   33. — Position    of    tube    for    e.xitosure    of    fust    film    in    making    dental    stereogram. 
Tube  tipped  inward  at  angle  of  7  J/   degrees. 


74 


INTEEPRETATIOjST    of    PvOENTGENOGEAMS 


satisfactory  in  a  bound  volume  to  give  illustrations  to  be 
viewed  stereoscopically. 

Localization  by  Comparison  of  Two  Films  Taken  in 
Different  Positions 

This  method  is  very  useful  in  determining,  for  example, 
whether  an  unerupted  tooth  lies  upon  the  lingual  or  the 


Fig.   34. — Position   of   tube  for   exposure   of   second   film   in   making   dental   stereogram. 
Tube  shifted  and  tipped  outward  at  angle  of  71/2   degrees. 

lal)ial  aspect  of  the  other  teeth.    The  j)rinciple  involved  is 
explained  by  the  following  example: 

(1)  Given  two  objects,  standing  in  a  straight  line  with 
the  observer,  the  more  distant  will  be  covered  by  the 
nearer. 

(2)  If  the  observer  moves  toward  the  right,  the  more 
distant  object  will  now  appear  to  be  to  the  right  of  the 
nearer  one. 

(3)  Again,  if  the  observer  moves  toward  the  left,  the 


METHODS    OF    LOCALIZATION  75 

nearer  object  will  appear  to  be  to  the  rigiit  of  the  farther 


one. 


In  other  words,  the  more  distant  object  apparently 
moves  in  the  same  direction  as  the  observer,  while  the 


Fig.   35. — Method    of    mounting    stereoscopic    films    so    that    they    may    be    adjusted    to 

desired    positions. 


Fig.   36. — Hand   stereoscope. 

nearer  object  apparently  moves  in  the  opposite  direction. 
This  is  further  brought  out  by  continuing  the  lines  of 
observation  through  each  object  on  to  a  screen  as  indi- 
cated in  the  diagram.     (Fig.  37.) 

Applying  this  principle  now  to  roentgenographic  films, 


76  INTERPRETATIOIsr    OF    ROENTGENOGRAMS 

if  an  uiierupted  tooth  is  to  the  lingual  side  of  the  other 
teeth ;  i.  e.,  farther  away  from  the  source  of  the  ray,  and 
two  films  are  made,  one  a  little  farther  to  the  right  than 
the  other,  the  unerupted  tooth  in  the  second  film  will  ap- 
pear to  be  farther  to  the  right  than  in  the  first  film.  On 
the  other  hand,  if  the  unerupted  tooth  lies  to  the  labial 
side  of  the  other  teeth,  i.  e.,  nearer  the  tube,  it  will  appear 
to  be  farther  to  the  left  in  the  second  film  than  in  the  first. 
In  locating  unerupted  canine  teeth,  which  frequently 
give  no  other  indications  whatever  as  to  their  lingual  or 
labial  situation,  this  principle  yields  valuable  assistance, 
in  cases  where  stereoscopic  films  may  be  difficult  to 
obtain. 


a*£r 

a,             €- 

\          " 

] 

'\        \ 

i?^ 

\       ^^ 

1 

I 

1 

1 
1 
t 

\      \ 
\      \ 

>    \ 

\  \ 

> 

^..-iohitr 

i>«r) 

1. 

2. 

TT 


/ 


/ 


/    O4, 

I  ' 
1/ 


\  i 


Fig.  37. 

1.  Two  objects  in  a  straight  line  with  the  observer;  the  more  distant  one  is  cov- 
ered by   the  nearer. 

2.  Observer  moves  to  the  right;  the  more  distant  object  is  apparently  to  the  right 
of   the   nearer   one. 

3.  Observer  moves  to  the  left;  the  nearer  object  is  apparently  to  the  right  of  the 
niore  distant  one. 

No  claim  to  originality  is  made  in  describing  the  above 
method,  which,  so  far  as  I  am  aware,  originated  with  Mr. 
C.  A.  Clark  in  Bennett's  Science  and  Practice  of  Dental 
Surgery.  The  ease  and  certainty  with  which  it  has  given 
the  desired  information  in  numerous  cases  warrants  its 
more  frequent  adoption  and  recognition,  which  up  to  now 
has  apparently  not  been  generally  accorded.  Practical 
examples  of  the  method  are  illustrated  in  Figs.  226,  227, 
228,  and  229,  pp.  128  and  129. 


PART  II 


CHAPTER  VII 

INTERPRETATION 

This  section  is  devoted  to  a  detailed  descrixDtion  and 
interpretation  of  numerous  illustrations.  Reproductions 
of  films  are  presented  showing  both  normal  and  abnor- 
mal conditions  in  every  part  of  the  mouth,  grouped  con- 
veniently for  comparative  study. 

The  interpretations  given  are  in  conformity  with  the 
anatomic,  pathologic,  and  clinical  data  discussed  in  the 
preceding  chapters. 

The  reproductions  of  all  plates  and  films  have  been 
made  so  as  to  resemble  the  originals  as  closely  as  pos- 
sible. Though  the  double  reduplication  rendered  neces- 
sary in  carrying  this  out  entails  some  loss  of  detail  which 
would  perhaps  not  be  so  marked  were  simple  prints  of 
the  negatives  used,  it  is  believed  that  shortcomings  in  this 
respect  are  outweighed  by  the  closer  resemblance  to  the 
originals  in  regard  to  light  and  dark  areas.  The  descrip- 
tions of  the  reproductions,  therefore,  would  apply  equally 
to  the  originals,  without  any  change  whatever.  In  illustra- 
tions of  roentgenograms  of  some  other  parts  of  the  body, 
this  transposition  back  to  the  original  form  is  perhaps 
not  so  important  because  these  other  regions  are  also  ex- 
amined fluoroscoiDically,  in  which  case  the  parts  appear 
as  they  do  in  a  print ;  i.  e.,  the  bones  and  dense  tissues 
appear  as  shadows  instead  of  light  areas  as  in  the  nega- 
tive. Since  the  fluoroscope  is  rarely  applicable  to  dental 
examination,  and  negatives  are  nearly  always  used,  it 
has  been  considered  advisable  to  reproduce  the  illustra- 

77 


78  IE"TERPRETATIO]S:    OF    ROENTGENOGRAMS 

tions  as  negatives,  so  as  to  more  closely  apiDroach  the  con- 
ditions of  examination  in  actual  practice. 

In  the  latter  part  of  this  section  are  described  several 
x-ray  plates  showing  various  conditions  such  as  impacted 
third  molars,  cysts,  fractures,  etc.,  in  which  plates  are 
frequently  of  more  value  than  films. 


INTERPRETATIOlSr    OF    ROENTGENOGRAMS 


79 


Upper  Anterior  Region 


<1  ^ 


Fig.   38. 


Fig.   39. 


Fig.  38. — Upper  centrals  and  right  lateral  normal.  Dark  area  at  top  on  right  side 
is   nasal   chamber. 

Fig.  39. — Upper  right  central,  lateral  and  canine:  Pulps  vital,  no  periapical  ab- 
normality. Floor  of  nose-  and  maxillary  sinus  barely  shown  as  dark  shadows  above. 
The  thin  dark  peridental  line  and  dense  white  bony  line  are  seen  about  roots.  Fill- 
ings   shown    as    dense    white    spots. 


Fig.   40. 


Fig.   41. 


Fig.  40. — Upper  left  central,  lateral,  canine  and  premolars:  Imperfect  root  canal 
fillings  in  canine  and  first  premolar,  shown  by  white  line  in  root;  no  periapical  ab- 
normalities  shown.      Ill-fitting   shell    crown   on   first   premolar. 

Fig.  41. — Upper  central  incisors:  Sharply  defined  dark  area  between  roots  is 
anterior  jialatine  fossa,  somewhat  resembling  the  appearance  of  bone  destruction  and 
cj-st  formation.  Ijoth  teeth,  however  contain  vital  puljis,  and  normal  peridental  line 
can  be  followed  around  each  root. 


80 


INTEEPRETATION    OF    EOENTGENOGRAMS 


Upper  Anterior  Region 


Fig.  42. 


Fig.  43. 


Pig,  42. — Upper  right  central  and  lateral  incisors:  Both  teeth  probably  contain 
vital   pulps;   periapical   tissue   normal. 

Fig.  43. — Upper  left  central  and  lateral  incisors:  Pulps  vital  as  shown  by  faradic 
test;  no  evidence  of  periapical  abnormality.  Some  interdental  alveolar  bone  de- 
struction   (pyorrhea). 


Fig.   44. 


Fig.  45. 


Fig.  44. — Upper  right  central,  lateral  and  canine:  Large  fillings  in  these  teeth; 
pulps  respond  to  faradic  test;   no  periapical   disturbance. 

Fig.  45.— Upper  central  incisors:  Pulps  vital,  no  periapical  abnormality.  Left 
laleral  missing.  The  dark  area  between  the  centrals  is  caused  by  the  anterior  pala- 
tine  fossa. 


INTERPRETATIOlSr    OF    ROENTGENOGRAMS 


81 


Upper  Anterior  Region 


Fig.  46. 


Fig.   47. 


Fig.  46. — ^^LTpper  left  central,  lateral,  canine  and  first  premolar.  Partial  root 
filling  in  centra!.  Crown  with  posts  and  no  root  filling  in  premolar.  No  periapical 
abnormalities.      Maxillary   sinus   shown   as   dark   area    above   premolar. 

Fig.  47. — Upper  right  central  forms  abutment  to  poorly  fitting  bridge,  which  ex- 
tends to  left  canine.  Upper  left  central  and  lateral  have  been  lost.  No  periapical 
abnormalities.     The  dark  area  above  is  the  nasal  fossa. 


Fig.   48. 


Fig.  49. 


Fig.  48. — Upper  right  lateral  incisor  shows  post  for  support  of  crown,  no  other 
root  filling;  ill-defined  dark  area  abovit  apex  due  to  chronic  rarefying  osteitis  with 
suppuration.      Nasal    fossa   with    inferior   turbinate    well    shown   above. 

Fig.  49. — Upper  right  lateral  incisor  contains  devitalized  pulp  (faradic  test)  under 
filling.  Ill-defined  dark  area  about  apex  due  to  chronic  rarefying  osteitis  with  sup- 
puration. 


82 


IlSrTERPKETATION    OF    ROENTGElsrOGRAMS 


Upper  Anterior  Region 


Fig.  50. 


Fig.  51. 


Fig.  50. — Upper  right  lateral  incisor  with  root  filling  extending  over  apical  end 
of  root  which  shows  absorption;  fairly  well-defined  dark  periapical  area,  due  to  chronic 
rarefying  osteitis  with  granuloma. 

Fig.  51. — Upper  left  lateral  incisor,  imperfect  root  filling;  irregular  absorption 
of  apex;  clearly  defined  rounded  dark  area,  probably  due  to  cyst  formation;  would 
expect  also  to  find  some  granulation  tissue  present.  Pulp  vital  in  central  incisor, 
though  the   apex  of  the  latter  is   apparently  involved   in  the  diseased   area. 


Fig.   52. 


Fig.   53. 


Fig.  52. — Upper  right  central  incisor,  good  root  filling  extending  slightly  beyond 
apex,  periapical  region  normal.  Upper  left  central  contains  devitalized  pulp,  shows 
irregular  absorption  of  root,  and  rarefying  osteitis  with  granuloma.  Nasal  foss<e  with 
inferior   turbinates   are   well   shown   above. 

Fig.  53. — Upper  left  central  incisor  crowned,  imperfect  loot  filling,  irregular  ab- 
sorption of  root,  and  chronic  rarefying  osteitis  with  granuloma.  Upper  right  central 
has   been   lost   and    replaced    by   a   bridge. 


IFTEEPKETATION    OF    ROENTGENOGRAMS 


83 


Upper  Anterior  Region 


Fig.   54. 


Fig.   55. 


Fig.  54. — Upper  right  central  contains  devitalized  infected  pulp;  the  dark,  fairly 
well-deiined  periapical  area  indicates  chronic  rarefying  osteitis  with  granuloma. 
Lvateral  incisor  pulpless,  imperfect  root  filling,  same  periapical  condition  as  m 
central. 

pjg,  55. — Upper  right  central,  pulp  vital,  periapical  tissue  normal.  Lateral  in- 
cisor crowned,  imperfect  root  filling,  chronic  rarefying  osteitis  with  granuloma.  Nasal 
chamber  seen  above. 


Fis.   56. 


Fig.  57. 


Fig.  56. — Upper  right  central  pulpless,  good  root  filling;  an  accessory  canal  is 
shown  passing  to  left  side  of  root  near  apex,  containing  root  filling;  dark  periapical 
area  due  to   chronic   rarefying   osteitis   and   granuloma. 

Fig.  57. — Upper  left  central  and  lateral  incisors  crowned,  imperfect  root  fillings; 
ajjices  surrounded  by  large  dark  area  due  to  chronic  rarefying  osteitis  and  granuloma. 


84 


INTERPEETATIOlSr    OF    ROENTGENOGRAMS 


Upper  Anterior  Region 


Fig-.    58. 


Fig.   59. 


Fig.  58. — Upper  right  central  and  left  lateral  incisors,  forming  supports  for 
bridge:  The  central  incisor  contains  imperfect  root  filling,  and  shows  dark  area  due 
to  rarefying  osteitis  and  granuloma  about  apex.  L,eft  lateral  shows  poorly  outlined 
area  due  to  osteitis  with  suppuration.  The  bony  support  of  this  tooth  has  been  largely 
destroyed  on  the  distal  aspect.  Right  lateral  incisor  crowned,  root  filling  passing 
through   apex   into  area   of  bone  destruction  with  granuloma. 

Fig.  59. — Upper  right  central  incis&r  contains  vital  pulp  and  shows  no  periapical 
abnormality.  L,ateral  shows  traces  of  root  filling  and  large  well-defined  area  about 
root  indicating  chronic   raref3'ing  osteitis  and  cyst  formation. 


Fig.   60. 


Fig.   61. 


Fig.  60. — Upper  left  central  crowned,  imperfect  root  filling,  slight  thickening  of 
peridental  line  at  apex,  indicating  chronic  pericementitis.  The  same  condition  is  seen 
in  connection  with  the  lateral  incisor  which  forms  the  anterior  abutment  of  a  bridge. 

Fig.  61. — Upper  right  central  and  lateral  incisors  crowned,  imperfect  root  fillings, 
jieridental  thickening  due  to  chronic  pericementitis  which  later  would  result  in  a 
definite  area  of  bone  destruction  and  granuloma,   suppuration   or   cyst   formation. 


INTEEPRETATIOISr    OF    EOENTGENOGEAMS 


85 


Upper  Anterior  Region 


Fig.  62. 


Fig.  63. 


Fig.  62. — Upper  right  lateral  incisor  crowned,  imperfect  root  filling,  peridental 
thickening  at  apex,   due   to   chronic  inflammatory  process.     Central   incisor  normal. 

Fig.  63. — Upper  right  central  incisor  with  large  apical  opening  and  pulp  chamber, 
due  to  arrested  development  probably  from  trauma;  secondary  infection  and  chronic 
rarefying    osteitis    with    granuloma. 


Fig.  64. 


Fig.  65. 


Fig.  64. — Upper  left  lateral  incisor  contains  infected  pulp,  no  root  tilling,  and  pre- 
sents ill-defined  periapical  area  due  to  chronic  rarefying  osteitis  and  suppuration.  Ca- 
nine normal. 

Fig.  65. — Upper  right  central  incisor  shows  extensive  decay  of  crown,  good  root 
filling,  no  periapical  disturbance.  Lateral  incisor  crowned,  perforation  of  distal 
side  of  root,  with  area  of  bone  destruction  at  this  point;  also  area  of  chronic  rare- 
fying  osteitis    and    granuloma   at   apex. 


86 


IlSrTEEPRETATIO:^'    OF    ROENTGENOGRAMS 


Upper  Anterior  Region 


Fig.  66. 


Fig.   67. 


Fig.  66. — Upper  left  central  incisor,  pulp  vital,  no  periapical  abnormality.  Upper 
right  central  has  good  root  filling  but  shows  dark  area  above  apex,  due  to  chronic 
rarefying  osteitis  with  granuloma.  Lateral  incisor  has  been  lost;  in  this  region  also 
is  found  a  dark  area,  due  to  rarefying  osteitis  remaining  after  extraction  of  tooth 
from  failure  to  curette  the  tooth  socket.  The  contents  of  this  area  are  just  as  much 
of  a   menace  as   of  the  area  connected  with   the  central  incisor. 

Fig.  67. — Upper  right  lateral  incisor  gave  no  response  to  faradic  test;  pulp  evi- 
dently died,  causing  chronic  rarefying  osteitis  shown  by  large  dark  area. 


Fig.  68. 


Fig.   69. 


Fig.  68. — Upper  left  central  incisor  crowned,  root  filling  to  apex,  no  evidence  of 
periapical  disease.  Lateral  incisor  crowned,  absorption  of  end  of  root,  with  large 
dark  periapical  area  with  ill-defined  borders,  probably  containing  granulation  tissue; 
lateral  perforation  of  root  by  post.  Canine  contains  a  vital  pulp  and  presents  no 
abnormality.      Large  dark   area  above   is   nasal   fossa. 

Fig.  69. — Upper  right  central  crowned,  no  sign  of  root  filling;  small  periauical 
dark  area  due  to  chronic  rarefying  osteitis  and  granuloma  foimation.  Lateral  in- 
cisor  pulpless,   peridental    thickening   at  apex. 


INTEEPRETATIOX    OF    EOEXTGEXOGRAMS 


87 


Upper  Anterior  Region 


Fig.   70. 


Fig.  71. 


Fig.    70. — Uvper    right    lateral    incisor    pulpless,    no    root  filling,    very    large    area 

of    chronic     rarefying    osteitis;     the     ragged     edges     indica^^e  probably     a     supnnrative 

process.      The    area    apparently    extends    to    the    apex    of    the  central    incisor,    but   the 
pulp   of  this   tooth   is   still   vital. 

Fig.  71. — Upper  right  lateral  incisor  forms  bridge  abutment;  no  periapical  disease 
shown,  but  there  is  loss  of  bony  support  due  to  pyorrhea.  Canine  shows  perfora- 
tion of  side"  of  root  by  post,  and  practically  no  root  filling.  First  premolar  crowned, 
no  root  fillings,  chronic  apical  pericementitis  shown  by  thickening  of  normal  peridental 
dtrk   line. 


Fig.  72. 


Fig.   73. 


Fig.  12. — Upper  right  lateral  incisor  and  canine,  both  used  as  supports  for  bridge. 
Lateral  shows  root  filling  passing  to  side  of  root,  and  also  irregular  area  of  bone  de- 
struction about  apex,  probably  due  to  chronic  rarefying  osteitis  with  granuloma. 
Canine  shows  apical  peridental   thickening. 

Fig.  ~Z. — Upper  right  central  and  lateral  incisors  normal.  Canine,  supporting 
bridge,  shows  large  perforation  of  mesial  side  of  root,  with  area  of  bone  destruction 
probably  containing  granulation  tissue  extending  over  to  lateral  incisor.  Apex  of 
canine  very  close  to  floor  of  nasal  chamber. 


INTERPEETATIOlSr    OF    ROENTGENOGRAMS 


Upper  Anterior  Re^on 


Fig.  74. 


Fig.   75. 


Fig.  74. — Apical  portion  of  root  of  upper  right  central  incisor  left  behind  after 
extraction.  The  piece  of  root  is  surrounded  by  an  area  of  chronic  rarefying  osteitis 
with  granuloma. 


Fig.  75. — Upper  right  central  incisor  showing  fracture  of  root  near  apex, 
producing  fracture  also  caused  death  of  pulp  and  chronic  abscess  with  sinus. 


Injury 


Fig.  76. 


Fig.  n. 


Fig.  76. — Upper  right  central  and  lateral  incisors,  pulps  vital,  no  periapical  abnor- 
mality; there  is  marked  bone  destruction  and  loss  of  support  of  roots  from  crowns 
toward  apices,  due  to  chronic  suppurative  osteopericementitis  (pyorrhea). 

Fig.  n. — Upper  right  central  and  lateral  incisors  missing,  being  replaced  by  bridge- 
work.  A  portion  of  hyi)odermic  needle  is  shown  at  site  of  central.  Canine  and 
premolars  show  posts  in  roots,  no  other  root  fillings,  and  evidences  of  chronic  apical 
pericementitis.      Apex  of  second  premolar   is  very   close   to   maxillary   sinus. 


INTERPKETATIOISr    OF    ROENTGENOGRAMS 


89 


Upper  Anterior  Region 


Fig.  7S. 


Fig.   79. 


Fig.  78. — Upper  right  central  incisor  contains  vital  pulp,  normal  peridental  line. 
I,ateral  incisor  dead  pulp,  large  area  of  bone  destruction  aliove  apex,  with  well-detined 
outlines  indicating  cyst  formation,  extending  up  to  floor  of  nose,  making  a  thin  par- 
tition at  this   point. 

Fig.  79. — Upper  incisor  region  covered  by  a  bridge,  all  teeth  having  been  lost.  At 
site  of  left  central  incisor  is  a  pear-shaped  dark  area  due  to  presence  of  a  cyst 
allowed  to  remain  behind  when  this  tooth  was  extracted  years  before;  there  were  no 
clinical  evidences  of  its  presence.     At  operation  the  cavity  contained   thick  pus. 


Fig.   SO. 


Fig.  81. 


Fig.  80. — Upper  right  central  crowned,  good  root  filling,  periapical  conditions  nor- 
mal. Lateral  incisor  crowned,  imperfect  root  filling,  large  periapical  area  extending  to 
floor  of  nose,  probably  due  to  cyst  formation  and  also  containing  some  granulation 
tissue. 

Fig.  81.— Upper  right  lateral  incisor  shows  root  filling  passing  through  apex  into 
large  periapical  area  of  chronic  rarefying  osteitis  with  ragged  edges  indicating  a  sup- 
purative process.  Pulp  vital  in  centr.n!  incisor,  the  apex  of  which  extends  to  edge  of 
area  of  disease. 


90 


Ii>TTEEPRETATION    OF    EOEISTTGEXOGEAMS 


Upper  Anterior  Region 


yMI 


Fig.  82. 


Fig.  83. 


Suture 


Fig.    82. — Supernumerary    tooth    between    roots    of   upper    central    incisors. 
line  is  clearly  shown. 

Fig.  83. — Pulp  in  upper  left  lateral  incisor  devitalized  by  blow.  The  same  trauma 
caused  a  transverse  fracture  of  alveolar  process  just  below  apex  of  lateral  incisor,  but 
did  not   fracture   root. 


Fig.  84. 


Fig.  85. 


Fig.  84.— tjpper  right  central  and  lateral  incisors  after  pulps  had  been  freshly  de- 
vitalized with  arsenic  and  root  canals  filled.  Fillings  are  seen  extending  to  apices. 
Area  of  disease  connected  with  canine  overlaps  root  of  lateral  but  does  not  involve  it. 

Fig.  85. — Film  of  same  teeth  made  one  year  later,  showing  absorption  of  both 
apices,  with  ends  of  root  fillings  extending  into  areas  of  destroyed  bone,  probably  the 
result  of  action  of  arsenic. 


INTEEPRETATIOlSr    OF    ROENTGENOGEAMS 


91 


Upper  Right  Region 


Fig. 


Fig.  87. 


Fig.  86. — Upper  right  side  from  canine  to  first  molar  inclusive;   nothing  abnormal. 

Fig.  87. — Upper  right  canine  normal.  First  premolar  good  root  filling,  apex  ex- 
tends close  to  floor  of  maxillary  sinus.  First  molar  roots  apparently  project  into 
m.axillary  sinus,  but  in  reality  are  in  the  wall  of  the  sinus;  furthermore,  this  tooth 
has  a   vital   pulp. 


Fig.  88. 


Fig.  89. 


Fig.  88. — Upper  right  canine  pulpless,  good  root  filling,  periapical  condition  normal. 
First  premolar  pulp  vital,  nothing  abnormal.  Second  premolar  missing;  above  the 
site  of  this  tooth  is  a  dark  adea  produced  by   the  maxillary   sinus. 

Fig.  89. — Upper  right  canine  and  premolar  normal.  First  molar  roots  project  above 
level  of  floor  of  maxillary  sinus,  but  the  normal  dense  line  of  bone  can  be  seen 
surrounding  the  roots.     The  pulp  of  this  tooth  also  is  vital. 


92 


IXTERPKETATIOi^    OF    EOEXTGEiSTOGEAMS 


Upper  Ri^ht  Re^on 


Fig.   90. 


Fig.   91. 


Fig.  90. — Upper  right  canine  and  first  premolar  normal.  Second  premolar  pulpless, 
partial  root  filling,  slight  peridental  thickening  at  apex.  The  dark  space  above  the 
premolars  is  the  maxillary  sinus,  separated  from  the  roots  of  these  teeth  by  a  thin 
plate  of  bone. 

Fig.  91. — Upper  right  canine  and  first  premolar  contain  vital  pulps.  Second  pre- 
molar and  first  molar  show  filled  roots  extending  up  to  but  not  encroaching  on 
maxillary  sinus. 


Fig.  92. 


Fig.  93. 


Fig.  92. — Relationship  of  roots  of  first  and  second  molars  to  maxillary  sinus  shown; 
they  project  above  the  level  of  the  floor,  but  do  not  encroach  on  cavity. 

Fig.    93. — Roots    of    second    premolar    and    first    molar    apparently    projecting    into 
maxillary  sinus,  but  a  thin  partition  of  bone  can  be  seen  covering  the  roots. 


USTTEEPRETATIOX    OF    ROEjSTTGEXOGRAMS 


93 


Upper  Right  Region 


Fig.   94.  Fig.   95. 

Fig.   94. — Normal  relationship  of  roots  of  premolars  and  molars  to  maxillary  sinus. 

Fig.  95. — First  molar  pulpless,  imperfect  fillings  in  buccal  roots;  lingual  root  filled 
to  ape.x;  no  periapical  abnormalities,  though  roots  apparently  project  into  maxillary 
sinus. 


Fig.   96. 


Fig.  97. 


Fig.  96. — First  premolar  crowned,  imperfect  root  filling,  peridental  thickening  at 
apex.  Second  premolar  crowned,  no  root  filling,  pulp  may  be  vital;  apex  very  near 
floor   of  maxillary   sinus.     First  molar  missing. 

Fig.  97. — First  and  second  premolars  pulpless,  partial  root  fillings,  no  abnormal 
periapical  conditions.  First  molar  missing,  and  floor  of  maxillary  sinus  projects  well 
down   between   second   premolar   and   second   molar. 


94 


INTERPRETATION    OF    ROENTGENOGRAMS 


Upper  Rig-ht  Region 


Fig.   98.  Fig.   99. 

Fig.  98. — Fii-st  premolar,  good  root  filling  in  buccal  root,  partial  filling  in  mesial 
root;  second  premolar,  partial  root  filling;  pericemental  thickening  about  apices  of 
Ijoth   teeth.      First  and  second   molar  normal,   third   molar   impacted. 

Fig.  99. — Canine  and  second  premolar  pulpless,  partial  root  fillings,  pericemental 
thickening  about  apices.  First  premolar  and  first  and  second  molars,  no  periapical 
abnormalities. 


Fig.    100. 


Fig.    101. 


Fig.   100. — Second  premolar,  good  root  filling,  periapical  thickening.      Second  molar, 
Ijadly   fitting  crown. 

Fig.    101. — Second  premolar  crowned,   partial   root   filling;   dark  periapical   area  with 
irregular  outline,   denoting  chronic  rarefying  osteitis  with  suppuration. 


INTERPRETATION    OF    EOENTGEjSTOGRAMS 


95 


Upper  Rig-ht  Region 


Fig.    102. 


Fig.    103. 


Fig.  102. — First  premolar  crowned,  imperfect  root  fillings,  periapical  rarefaction, 
probably  with  suppuration.  First  molar  pulpless,  probably  chronic  rarefying  osteitis 
with  granuloma  at  apex  of  lingual  root. 

Fig.  103. — First  premolar  i)uli)less,  no  root  fillings,  area  of  periapical  rarefying 
osteitis  with   granuloma. 


Fig.  104. — Canine,  premolars  and  molars  show  absent  or  imperfect  root  fillings, 
liadly  fitting  crowns,  and  overhanging  edges  of  fillings.  First  premolar,  large  area  of 
periapical   bone  destruction,    probably   suppuration,   and   erosion   of   cementum. 

Fig.  105. — Upper  right  first  molar  crowned,  palatal  root  shows  area  of  jicriapical 
bene   destruction   probably    e.xtending   into    maxillary   sinus. 


96 


INTERPRETATION^    OF    ROENTGENOGRAMS 


Upper  Right  Region 


Fig.   106. 


Fig.   107. 


Fig.  106. — The  partition  of  bone  between  the  second  molar  and  the  maxillary 
sinus  has  been  destroyed  by  periapical  d'sease,  producing;  a  direct  communication  of 
this  tooth  with  the  maxillary  sinus  and  secondary  infection  of  that  cavity.  The 
second  premolar,  although  containing  a  part'al  root  rtUing,  and  _  presenting  some 
periapical  thickening,  is  separated  from  the  antrum  by  a  bony  partition.  The  apices 
of  the  canine  and  first  premolar  show  nothing  abnormal,  but  lie  very  close  to  the  floor 
of   the   sinus. 

Fig'.  107. — Second  premolar  crowned,  partial  root  filling,  periapical  region  normal. 
First  molar  crowned,  imperfect  root  fillings,  erosion  of  cementum  and  large  periapical 
area  of  chronic  rarefying  osteitis  with  suppuration  and  granuloma.  Note  floor  of 
maxillary  sinus  just  above  this  area. 


Fig.   1( 


Fig.    109. 


Fig.  108. — First  premolar  crowned,  practically  no  root  filling,  small  periapical  area 
of  chronic  rarefying  osteitis  with  granuloma.  Second  premolar  normal.  Part  of  first 
molar  root  extending  into  maxillary  sinus. 

Fig.    109. — Small   apical   portion    of   first   molar   root  in   maxillary   sinus. 


IXTERPr>ETATIOX    OF    ROEXTGEXOORAMS 


97 


Upper  Right  Region 


Fig.    110. 


Fig.    111. 


Fig.  110. — Upper  right  first  premolar  crowned,  partial  root  filling,  periapical  area 
of    bone   destrnction   due   to   chronic    rarefying   osteitis   with   granuloma. 

Fiff.  111. — l'|iper  right  second  premolar  crowned,  partial  root  filling;  periapical 
granuloma.  Considerable  thickness  of  bone  between  the  diseased  area  and  the  max- 
illary sinus. 


Fig.    112. 


Fi.g.   113. 


Fig.  112. — Upper  right  second  premolar  ]nil|:iless,  very  imjierfect  root  filling,  i)eri- 
apical  area  of  rarefying  osteitis  with  granuloma,  separated  by  very  thin  septum  of 
bone  from  maxillary  sinus. 

Fig.  113. — Upper  right  second  premolar  probably  contains  infected  pulp;  area  of 
jieriapical  bone  destruction  with  granuloma  separated  by  thin  partition  from  maxillary 
sinus,    forming  a  distinct   prominence   in   its  floor. 


ustterpketatiojst  of  roentgenograms 


Upper  Right  Region 


Fig.   114. 


Fig.   115. 


Fig.  114. — Second  premolar  infected  pulp  canal,  no  evidence  of  root  filling,  large 
periapical  area  of  chronic  rarefying  osteitis  with  granuloma,  separated  from  max- 
illary  sinus  by  thin  plate  of  bone  which  forms  a  prominence  in   its  floor. 

Fig.  115. — First  premolar  infected  pulp  canal,  no  evidence  of  root  filling;  periapical 
area  of  chronic  rarefying  osteitis  and  granuloma  reaching  up  to  floor  of  maxillary 
sinus. 


Fig.   116. 


Fig.   117. 


Fig.  116. — Upper  right  first  premolar  forms  abutment  of  bridge;  transverse  frac- 
ture of  root  at  junction  of  upper  and  middle  thirds. 

Fig.  117. — Large  lateral  area  of  bone  destruction  in  region  of  upper  right  canine. 
Second  premolar  crowned,  imperfect  root  filling,  apical  region  normal.  Dark  area 
over  first  molar  is  due  to  a  recess  in  the  maxillary  sinus.  First  molar  has  a  vital 
pulp  and  no  abnormality  about  roots. 


INTERPRETATIOlSr    OF    EOENTGENOGRAMS 


99 


Upper  Left  Region 


Fig.   118. 


Fig.    119. 


Fig.  118. — Upper  left  teeth  from  central  incisor  to  second  premolar,  pulps  vital, 
periapical  conditions  normal.  Destruction  of  bony  septum  between  lateral  incisor  and 
canine  due  to  pyorrhea.     Apex   of  second  premolar  near  floor   of  maxillary   sinus. 

Fig.  119. — Normal  lateral  incisor,  canine,  first  and  second  premolars,  and  first 
molar.  Pulps  all  vital.'  Maxillary  sinus  does  not  extend  farther  forward  than  first 
molar,  and   is  seen  just  above   apices   of  this   tooth. 


Fig.   120. 


Fig.    121. 


Fig.   120. — Roots   of   upper   left  teeth    from    central    incisor    to    second   premolar,    all 
normal. 

Fig.    121. — Maxillary    sinus    extends    well    forward    over    apex    of    canine.      No    ab- 
normal   periapical    conditions. 


100 


IjSttekpeetatioi^  of  roentgenograms 


Upper  Left  Region 


Fig.    122. 


Fig.    123. 


Fig.  122. — Upper  left  first  premolar  crowned,  partial  root  filling,  periapical  region 
normal.  First  molar,  crown  with  overhanging  edge,  apices  normal  though  appar- 
ently projecting  into  maxillary  sinus. 

Fig.  123. — Upper  left  canine  to  third  molar.  All  apical  regions  normal.  First 
molar  probably  missing,  and  rudimentary  third  molar  present,  koots  of  second  molar 
shown  in  wall  of  maxillary  sinus. 


Fig.    124. 


Fig.    125. 


Fig.   124. — Upper  left  canine,  and  first  and  second  premolars.     Pulps  vital.    Normal 
pericemental  line  seen  around  roots.      Floor  of  maxillary  sinus  also  shown. 

Fig.   125. — No  periapical  abnormalities.    Apices  of  second  premolar  and  first  molar 
very   close  to  floor   of   ma'cillary   sinus. 


INTERPEETATION    OF    ROENTGENOGRAMS 


101 


Upper  Left  Region 


Fig.    126. 


Fig.   127. 


Fig.  126. — First  molar  has  large  filling  on  distal  aspect.  Outline  of  disto-buccal 
root  is  indistinctly  shown  above  this.     Bone  destruction  around  filling  causes  a  pocket. 

Fig.  127. — First  premolar  crowned,  two  roots,  one  much  foresliortened;  good 
root  fillings,  apices  normal.  Other  teeth  normal.  First  molar  missing.  Second  and 
third   molar   roots   overshadowed   by  malar  bone. 


IPI 

WM 

n 

»-.■' 

.''WB 

k. 

J 

|1 

s 

Fig.   128. 


Fig.   129. 


Fig.  128. — Upper  left  premolars,  inilps  vital,  periapical  regions  normal.  Circum- 
scribed dark  area  about  apex  of  second  premolar  somewhat  resembling  an  area  due 
to  rarefying  osteitis  is  only  due  to  a  recess  in  the  maxillary  sinus;  the  normal  line  of 
bone  can  be  traced  completely  around  the  apex  of  this  tooth.  Light  shadow  in  upper 
left  corner  is  due  to   malar  bone. 

Fig.  129. — -Upper  left  first  premolar  crowned,  imperfect  root  fillings,  periapical 
region  normal.  Second  premolar  pulp  vital.  The  white  line  apparently  running  from 
its  apex  is  due  to  a  septum  in  the  maxillary  sinus. 


102 


IlsrTEEPEETATIOlSr    OY    ROENTGENOGRAMS 


Upper  Left  Region 


Fig.   130. 


Fig.    131. 


Fig.  130. — Upper  left  second  pre.-nolar  pvilpless,  no  root  canal  filling;  thickening 
of  peridental  membrane  due  to  inflammation  about  apex,  which  is  ver\'  close  to  floor 
of   ma-xillary  sinus. 

Fig.  131. — Upper  left  canine,  root  tilling  only  extends  about  half  way,  apex  ap- 
parently encapsulated  with  healthy  bone.  First  premolar  crowned.  The  tdm  is  over- 
exposed, but  shows  that  the  root  of  this  tooth  is  absorbed  and  surrounded  by  area 
of  bone  destruction  with  granuloma.  Second  premolar  crowned,  partial  root  filling, 
with  apex  involved  in  a  common  area  of  l^one  destruction  and  granuloma  with  mesio- 
buccal  root   of  first  molar  which  contains   no  root  filling. 


Fig.    132. 


Fig.   133. 


Fig.  132. — Upper  left  premolars  and  molars  have  poorly  fitting  crowns,  responsible 
for  gingival  infectdon  and  absorption  of  bone  around  necks  of  teeth.  First  premolar 
shows  no  root  filling  and  peridental  thickening.  Second  premolar,  partial  root  filling, 
periapical  bone  destruction  and  granuloma.  Same  condition  of  first  molar.  Second 
m.olar,   probably   no   periapical   disease,   but   buccal   roots   denuded   from   pyorrhea. 

Fig.  133. — Upper  left  first  premolar  crowned,  no  root  filling,  post  of  crown  per- 
forating side  of  root;  about  site  of  perforation  is  an  area  of  chronic  rarefying  osteitis 
with   granuloma;    periapical   thickening   of   peridental   membrane. 


INTERPRETATION    OF    ROENTGENOGRAMS 


103 


Upper  Left  Region 


Fig.   134. 


Fig.   135. 


Fig.  134. — Upper  left  first  premolar,  decay  under  filling.  Second  premolar 
crowned,  imperfect  root  filling,  which,  however,  extends  to  apex,  periapical  region 
normal.  First  molar  pulpless,  apparent  area  of  rarefaction  about  apex  of  lingual 
root,  but  close  scrutiny  reveals  cancellated  bone  in  this  position.  A  bony  promi- 
nence over  this  tooth  projects  into  maxillary  sinus. 

Fig.  135. — First  premolar  shows  fracture  of  root  at  junction  of  upper  and  middle 
thirds;  pulp   of  this  tooth  remained  vital  for  several  years  after  fracture. 


Fig.   136. 


Fig.   137. 


Fig.  136. — Upper  left  maxillary  sinus  extends  forward  to  canine,  which  is  normal. 
First  premolar  crowned,  periapical  thickening  of  peridental  membrane  due  to  chronic 
proliferative  pericementitis.  Second  premolar  vital  pulp,  apex  normal,  though  extend- 
ing to  floor  of  maxillary  sinus.  First  molar  crowned,  periapical  area  of  bone  destruc- 
tion  about   lingual   root,   in  wall   of   maxillary   sinus. 

Fig.  137. — Apex  of  second  premolar  insufficiently  shown  for  diagnosis.  First 
molar  crowned,  imperfect  root  fillings,  chronic  periapical  rarefying  osteitis  with 
granuloma,   extending  to   floor  of   maxillary   sinus. 


104 


INTERPRETATIOiSr    OF    ROElN^TGElSrOGEAMS 


Upper  Left  Region 


■-.l*^ 

M 

HMH^^ 

1 

i 

7-          l^^^l 

Fig.    138.  Fig.    139. 

Fig.  138. — Large  sharply  defined  area  of  bone  destruction  above  premolars  and 
first  molar.  Probably  cyst  formation  arising  in  connection  with  first  molar,  whose 
roots  are  seen  to  be  eroded.  The  cyst  cavity  probaljly  enci  caches  on  the  maxillary 
sinus,  which,  is   seen  above  the  second  molar. 

Fig.  139. — First  premolar  crowned,  partial  root  filling,  apex  probably  normal. 
Second  premolar  crowned,  partial  root  fillings,  apex  probably  normal.  First  molar 
shows  a  large  area  of  bone  destruction  about  apex  of  lingual  root.  Absence  of  root 
fillings  would  indicate  presence  of  dead  pulp.  Destruction  of  bone  septum  between 
first  and  second  molars  due  to   pyorrhea   from   overhanging   edge   of   filling. 


Fig.    141. 


Fig.  140. — Condition  about  premolars  is  ill-defined,  owing  to  overexposure  of 
film.  First  molar  crowned,  imperfect  root  fillings.  Apex  of  lingual  root  is  seen  in 
wall  of  maxillary  sinus  surrounded  by  an  area  of  bone  destruction  which  probably 
communicates  with  the  sinus.  The  bony  septum  between  the  two  molars  is  destroyed 
by  pyorrhea  except  its  apical  third.      Practically   no  bony   attachment   to   second  molar. 

Fig.  141. — First  premolar  pulpless,  poor  root  filling,  periapical  thickening  of  peri- 
dental membrane  due  to  chronic  proliferative  pericementitis.  Apex  very  close  to 
maxillary  sinus.  Large  area  of  bone  destruction  with  granuloma  ahout  apices  of  last 
molar. 


IliTTERPRETATIOlSr    OF    ROENTGENOGRAMS 


105 


Upper  Left  Region 


Fig.    142. 


Fig.    143 


Fig.   142. — Second   premolar,    partial    root    filling,    apex    normal.      Apical    portion    of 
root  of   first   molar   remaining  after   extraction. 

Fig.    143. — Upper    left    second    molar    forms    posterior    abutment    of    bridge.     Bone 
completely   destroyed   around   buccal  roots. 


Fig.    144. 


Fig.   144. — First    premolar,    perforation    of    side    of    root    with    large    area    of    bone 
destruction  surrounding  the  perforation;   apex  normal. 

Fig.    145. — Apical  region  of  crowned  premolars  normal.     First  molar   missing.     Deep 
[locket   due   to   pyorrhea  just   in  front   of  second   molar. 


106 


I]SrTEEPEETATIO:N-    OF    KOE^STTGEXOGEAMS 


Upper  Left  Region 


.     mm- 

a 

Lii. 

Fig.    146. 


Fig.    147. 


Fig.  1411. — Decay  beginning  on  mesial  surface  of  upper  left  canine  near  cervical 
margin.  First  premolar  crowned,  two  roots,  apparently  good  root  fillings,  large,  irreg- 
ular, clearly  defined  periapical  area  of  chronic  rarefying  osteitis  with  granuloma.  Sec- 
ond premolar  normal. 

Fig.  147. — First  molar,  pulp  probably  vital;  extensive  jjyorrheal  bone  destruction, 
extending  between  roots.  Second  molar,  badly  fitting  crown,  poor  root  fillings,  but 
apical   region  normal. 


Fig.   148. 


Fig.    149. 


Fig.  148. — Upper  left  canine  and  first  premolar  normal.  Impacted  first  molar,  sur- 
rounded  by  an  area   of  bone  destruction  involving  apex   of  second  premolar. 

F'ig.  149. — Upper  left  canine  pulpless,  apparently  good  root  filling,  considerable 
]ieriapical  area  of  bone  destruction  with  granuloma.  Dark  area  to  left  is  maxillary 
sinus. 


II^TERPFvETATIOX    OF    EOEXTGEXOGEAMS 


107 


Upper  Left  Region 


Fig.   150. 


Fig.   151. 


Fig.  150. — First  premolar  crowned,  no  root  filling,  marked  curvature  of  root,  apex- 
normal.  Second  premolar  crowned,  partial  root  filling,  periapical  chronic  rarefying 
osteitis  with  granuloma.  This  area  forms  a  projection  which  is  walled  off  from  the 
maxillary  sinus  by  a  thin  plate  of  bone. 

Fig.  151. — Upper  left  first. premolar  crowned,  imperfect  root  filling,  no  periapical 
abnormality.  Second  premolar,  poorly  fitting  crown,  leading  to  infection  and  ab- 
sorption of  alveolar  septum;  apparently  good  root  filling;  periapical  bone  destruction, 
granuloma,   and   roughening   of   apex. 


Fig.    15: 


153. 


Fig.  152. — Second  premolar  crowned,  with  decay  shown  under  edge  of  crown;  no 
root  filling,  canal  probably  contains  necrotic  pulp  tissue;  chronic  larefying  osteitis 
with  granuloma  about  apex,  which  projects  above  floor  of  maxillary  sinus,  but  is  sep- 
arated from  it  by  a  thin  plate  of  bone.  White  line  extending  vertically  upward  from 
apex  indicates  a  septum  in  maxillary  sinus. 


153. — -Upper   left    second    premolar,    death    of   pulp    under    filliiiE 
ajiical    area   of   bone   destruction   indicating   suppuration. 


Ill-defined    peri- 


108 


HSTTERPRETATION    OF    ROENTGENOGRAMS 


Upper  Left  Region 


Fig.   1S4. 


Fig.   155. 


Fig.  154. — Second  premolar,  bridge  abutment,  nothing  abnormal  .seen  at  apex. 
First  molar,  death  of  jnilp  beneath  filling;  area  of  bone  destruction  about  apex  of 
palatal  root,   well   above  floor   of   maxillary   sinus. 

Fig.   155. — Another  view   of  first  molar  shown  in   opposite   illustration. 


Fi.^.    156. 


Fig.    157. 


Fig.  156. — Upper  left  lateral  incisor  crowned,  post  does  not  follow  root  canal, 
Ijut  passes  to  side  of  root,  no  root  filling,  apical  region  apparently  normal.  Canine, 
large  filling  extending  to  pulp  chamber,  no  root  filling,  root  canal  evidently  contains 
infected  pulp  tissue;  large  area  of  chronic  rarefying  osteitis  with  granuloma  around 
apex  of  this  tooth  and  extending  almost  down  to  neck  on  mesial  side.  First  pre- 
molar crowned,  extensive  root  absorption  and  chronic  periapical  rarefying  osteitis 
with  granuloma,  extending  to  root  of  second  premolar.  Second  premolar,  decay  on 
distal  surface;   above  this   is  a   jiartial   loss   of  alveolar   septum  due   to   pyorrhea. 

Fig.  157. — First  premolar  pulpless,  no  root  filling,  apex  involved  in  large  area  of 
chronic  rarefying  osteitis  with  granuloma  extending  to  region  of  second  premolar, 
which  has  been  lost. 


II^TERPRETATION    OF    ROENTGENOGRAMS 


109 


Upper  Left  Region 


Fig.   158. 


Fig.   159. 


Fig.  158. — Large  area  of  chronic  rarefying  osteitis  with  clearly  defined  walls  in- 
dicating cyst  formation.  This  has  probably  arisen  from  infection  connected  with  the 
first  premolar,   which  is  crowned,  and   contains  an  imperfect  root  filling. 

Fig.  159. — Same  case  as  in  opposite  film,  following  extraction  of  first  premolar  and 
curettement  of  cyst  cavity.  Taken  six  weeks  later;  regeneration  of  bone  is  taking 
place,  as  indicated  by  haziness  of  outline  of  cavity,  and  lessening  in  size  of  rarefied 
area. 


Fig.   160. 


Fig.   161. 


Fig.  160. — Large  area  of  bone  destruction  in  region  between  upper  left  second 
jiremolar  and  first  molar;  irregular  margins  indicating  chronic  rarefying  osteitis  with 
suppuration.  Permanent  canine  and  second  molar  unerupted.  Infection  probably 
arose  in  connection   with   deciduous  molar. 

Fig.  161. — Distortion  present,  but  film  shows  large  area  of  bone  destruction  around 
pulpless  upper  left  first  molar,  apparently  communicating  directly  with  the  maxil- 
lary  sinus. 


110 


nSTTEEPRETATTON    OF    ROENTGENOGRAMS 


Lower  Front  Region 


Fig.   162. 


Fig.   163. 


Fig.   162.— Lower    central     and    lateral    incisors,     pulps    vital,     normal     bony    jc-ray 
anatomy. 

Fig.   163. — Lower    central    and    lateral    incisors,    normal. 


Fig.    164. 


Fig.    165. 


Fig.   164. — Lower   right    central   and   lateral    incisors   in   center   of    film;    pulps   vital, 
bone  normal. 

Fig.    165. — Lower   central   and   lateral   incisors,   normal. 


INTERPRETATIOIir    OF    ROENTGE^STOGRAMS 


111 


Lower  Front  Region 


'"% 

^Tl 

IP 

•^o 

H^ 

Fig.   166. 


Fig.   167. 


Fig.  166. — Area  of  chronic  rarefying  osteitis  with  granuloma  about  apices  of 
lower  right  central  and  lower  left  central  and  lateral  incisors.  It  is  difficult  to  tell 
which  of  these  teeth  is  responsible  as  all  contain  dead  pulps. 

Fig.  167. — Lower  right  central  incisor  pulpless,  partial  root  filling,  periapical  area 
of   chronic   rarefying  osteitis  with  granuloma. 


Fig.    168.  Fig.   169. 

Fig.   168. — Dead    pulp    in    lower    left  lateral    incisor.       Periapical    area    of    chronic 
rarefying   osteitis   with   suppuration. 

Fig.    169. — Lower    left    lateral    incisor  pulpless;    root    filling    extends    through    ape.x 

into  previously  existing  bone  cavity   due  to   chronic   rarefying  osteitis. 


112 


INTERPRETATIOiSr    OF    EOEISTTGENOGEAMS 


Lower  Front  Region 


Fig.    170. 


Fig.    171. 


Fig.  170. — Dead  pulp  in  lower  right  central  incisor;  periapical  area  of  chronic  rare- 
fying  osteitis   with  granuloma. 

Fig.  171. — lyarge  area  of  bone  destruction  with  sharply  defined  edges  due  to  cyst 
involving  roots  of  lower  right  central  and  lateral  and  left  central  incisors.  Left  lat- 
eral incisor  missing.  Pulps  dead  in  central  incisors,  but  vital  in  right  lateral  and 
left  canine.  Cyst  probably  followed  chronic  rarefying  osteitis  in  connection  with 
death  of  the  pulp  of  one  of  the  central  incisors.     <Case  referred  by  Dr.  J.   S.   Evans.) 


Fig.    172. 


Fig.   173. 


Fig.  172. — lyower  right  central  and  left  central  and  lateral  incisors,  showing  ex- 
tensive_  destruction  of  bony  septa  between  teeth  from  cb.ronic  suppurative  peri- 
cementitis  (pyorrhea).     Right  lateral   incisor  has  already  been  lost  from  this  cause. 

Fig.  173. — Lower  front  teeth.  Moderate  destruction  of  alveolar  septa  due  to 
chronic  suppurative  pericementitis.  In  the  case  of  the  right  central  incisor  the  infec- 
tion extends  completely  around  the  apex  of  the  root  as  shown  by  the  thickened  peri- 
dental  line. 


INTEriPrtETATION    OF    EOEjSTTGEISrOGrvAMS 


11^ 


Lower  Front  Region 


Fig.    174. 


Fig.   175. 


Fig.  174. — Extensive  destruction  of  alveolar  process  following  pyorrhea.  Riglit 
canine  shows  roughening  of  root  due  to  deposit  of  calculus.  Right  lateral  incisor, 
ill-litting  crown,  partial  root  lilling,  apical  region  normal.  Kight  central  incisor  and 
first  premolar  missing. 

Fig.  175. — Right  central  incisor;  dead  pulp  causing  periapical  rarefying  osteitis 
and  granuloma. 


Lower  Right  Region 


Fig.  176. 


Fig.   177. 


Fig.  176. — Lower  right  canine  normal;  iirst  i)remolar  normal;  second  premolar 
jiulpless,  imperfect  root  filling,  periapical  tliickening  of  jieridental  membrane.  Be- 
tween and  below  apices  of  premolars   is  seen   a   dark   area  due   to   mental   foramen. 

Fig.  177. — Lower  right  premolar  and  molar  region.  No  bony  abnormalities.  Par- 
tial  root   tillings   in   first  and   second   molars. 


114 


iis:terpretation^  of  eoentgexogeams 


Lower  Right  Region 


Fig.   178. 


Fig.   179. 


Fig.   178. — lyower  right  second  premolar   has  a  poorly   fitting  crown,   pulp   probably 
vital,  apical  region  normal.     First  molar,   decay   of  approximal   surfaces   of   crown. 


Fig.   179. — L,ower   right   premolar   and   molar   region. 
Partial  root  fillings  in  first  and   second  molars. 


No   bony   abnormalities   seen. 


^4 


Fig.   180. 


Fig.   181. 


Fig.  180. — Lower  right  canine,  caries  of  distal  surface  of  crown.  First  and  sec- 
ond premolars  crowned,  partial  root  fillings,  periapical  chronic  rarefying  osteitis  and 
granuloma. 

Fig.  181. — Second  premolar,  pulp  vital,  no  apical  abnormality.  First  molar 
crowned,  partial  root  fillings,  ill-defined  area,  probably  indicating  suppuration  about 
apex   of   anterior   root.      Second   molar,    pulp   vital,   no   apical    abnormality. 


INTERPEETATION"    OF    ROEXTGEXOGP.AMS 


115 


Lower  Right  Region 


Fig.   182. 


Fig.   183. 


Fig.  182. — Lower  right  first  premolar,  pulpless,  apparently  good  root  filling,  no 
periapical  abnormality.  Second  premolar  recently  removed.  Inferior  dental  canal 
seen  curving  up  to  mental  foramen  near  socket  of  this  tooth.  First  molar,  large 
filling  and  caries  of  crown.     No  abnormality  of  bone. 

Fig.  183. —  Second  premolar,  too  indistinct  for  interpretation.  First  molar  miss- 
ing, as  indicated  by  space  and  inclination  of  teeth.  Second  molar  pulpless,  partial 
root  fillings,  periapical  thickening  due  to  chronic  pericementitis  about  anterior  root. 
Third   molar  pulp   vital,    no   abnormalities. 


Fig.    184. 


Fig.    185. 


Fig.  184. — Lower  right  second  premolar,  caries  beneath  lower  edge  of  filling,  no 
periapical  abnormality.  First  molar  pulpless,  partial  root  fillings,  periapical  thicken- 
ing of  pericementum  about  both  apices.  Mandibular  canal  indicated  by  two  shar|i 
parallel   lines  with  dark  space  between,   beneath  roots  of  molars. 

Fig.  185. — Second  premolar,  mesial  side  of  crown  broken  away.  First  molar, 
broken  down  filling,  partial  root  fillings,  periapical  thickening  of  pericementitis.  Sec- 
ond molar  pulpless,  no  root  fillings,  ill-defined  periapical  area  due  to  chronic  rarefying 
osteitis  with  suppuration.  Small  piece  of  root  of  third  molar  is  seen.  Diagonal  light 
lines  in  lower  corners  are  due  to  bending  of  film. 


116 


INTERPRETATION^    OF    ROEjSTTGEjSTOGRAMS 


Lower  Right  Region 


Fig.   186. 


Fig.   187. 


Fig.  186. — IvOwer  right  first  premolar  forms  bridge  abutment,  partial  root  filling, 
periapical  region  normal;  bone  absorption  around  neck  of  tootli  due  to  pyorrhea.  Sec- 
ond premolar  forms  bridge  abutment,  pulp  probably  vital,  periapical  region  normal. 
First  and  second  molars  missing. 

Fig.  187. — Child  fourteen  years  of  age.  First  and  second  premolars,  pulps  vital. 
Incomplete  calcification  of  apices.  first  molar  pulpless,  crown  badly  broken  down, 
imperfect   root   fillings,    apices   imperfectly   calcified. 


Fig.    188. 


Fig.   U 


Fig.  188. — Lower  right  second  premolar  partially  impacted  against  first  premolar. 
Pulps  vital   in   all   teeth.      No   bony   abnormalities. 

Fig.  189. — Second  premolar,  poorly  fitting  crown,  partial  root  filling,  periapical 
region  normal.  First  molar  pulpless,  imperfect  root  fillings,  peridental  thickening  at 
apices,  and  condensation  of  bone  around  distal  apex.  Broken  down  roots  of  second 
molar,  with  periapical  thickening. 


INTERPRETATIOlSr    OF    EOEXTGENOGEAMS 


117 


Lower  Left  Region 


'"~^^*^H 

HP 

HI 

'  -6 

hi 

N 

'I^^IhII^HM! 

■ft 

r 

Fig.   190. 


Fig.   191. 


Fig.   190. — lyOwer  left   premolar  and   molar   region,   showing   no   bony  abnormalities. 
First  molar  pvtlpless,   partial   root   fillings. 

Fig.   191. — Lower  left  molar  region.     No  bony  abnormalities.     First  molar  crowned, 
pulp  probably  vital.      Small   piece  of  root  of  third  molar  seen. 


Fig.   192. 


Fig.  193. 


Fig.   192. — Lower   left   molar    region,    no    bony   abnormalities.      Second    premolar    is 
partially  impacted.     Caries  of  crown  of  third  molar. 

Fig.   193. — Lower    left    premolar    and    molar    region.      First    molar    crowned,    partial 
root  fillings,   no   periapical   abnormalities. 


118 


INTEEPEETATIOjST    of   EOEiTTGE:NOGEAMS 


Lower  Left  Region 


Fig.   194.  Fig.   195. 

Fig.   194. — Lower  left  premolar  and  molar  regions,   no   bony  abnormalities. 

Fig.  195. — Lower  left  first  and  second  premolars,  pulps  vital.  Between  these  teeth 
is  seen  a  dense,  well-defined  mass,  that  might  be  mistaken  for  a  piece  of  root  were  it 
not  that  all  teeth  are  in  place.  This  shadow  is  due  to  a  subperiosteal  bony  nodule 
on  lingual  aspect  of  alveolar  ridge,  of  no  pathological  significance.  Beneath  this  is 
seen  the  mental  foramen.  First  molar  crowned,  partial  root  fillings,  no  periapical 
abnormality. 


Fig.    196. 


Fig.   197. 


Fig.  196. — Over  exposed.  I,ower  right  second  molar  crowned,  anterior  root  ap- 
parently well  filled,  no  filling  in  posterior  root;  large  periapical  area  embracing  both 
roots,   chronic  rarefying  osteitis  with  granuloma. 

Fig.  197. — Lower  left  canine  crowned,  partial  root  filling,  peridental  thickening 
at  apex;  post  of  crown  perforates  side  of  root;  about  the  perforation  is  an  area  of 
chronic  rarefying  osteitis  with  granuloma.  First  premolar  crowned,  partial  root  fill- 
ing, periapical  thickening  of  pericementum.  Second  premolar  crowned,  partial  root 
filling,   no  periapical  abnormality   shown.      First  molar  too   distorted   for  interpretation. 


IK'TEEPEETATIOX    OF    EOEXTGEXOGRAMS 


119 


Lower  Left  Region 


Fig.   IS 


Fig.   199. 


Fig.  198. — Lower  left,  first  molar  missing.  Second  molar  shows  caries  under  dis- 
tal portion  of  filling,  extending  to  pulp  chamber;  large  ill-denned  periapical  area  of 
chronic  rarefying  osteitis  with  suppuration.  Second  molar  ciowned,  partial  root  fill- 
ings, no  periapical  disease  evident. 

Fig.   199. — ^Lower  left  first  molar,  extensive  caries  of  crown;  no  bony  abnormalities. 


Fig.   200. 


Fig.   201. 


Fig.   200. — Lower    left    first    molar,    caries    of    distal    side,    not    quite    extending    to 
pulp  chamber;   no  periapical   abnormalities. 

Fig.   201. — Child,   fourteen  years   of  age.      First   and   second   premolars,   pulps  vital, 

incomplete  calcification  of  apices.     First  molar  pulpless,  partial  root  fillings;   this  tooth 

and  also   the  second   molar   show   incomplete   calcification   of   roots.      Unerupted  third 
molar  is  shown. 


120 


INTERPRETATION    OF    ROENTGENOGRAMS 


Lower  Left  Region 


Fig.   202. 


Fig.   203. 


Fig.  202. — Lower  left,  broken  down  roots  of  first  molar  with  peridental  thicken- 
ing. Second  molar  pulpless,  partial  root  fillings,  apical' ends  of  roots  hypercementosed; 
ill-defined  periapical   area,   denoting  suppuration. 

Fig.  203. — Lower  left  first  molar  missing.  Second  molar  pulpless,  good  root  fill- 
ing, extending  into  previously  existing  cavity  in  bone  resulting  from  chronic  rarefy- 
ing osteitis;  thickening  of  peridental  membrane  about  anterior  root.  Third  molar 
pulpless,  good  root  fillings,  extending  slightly  through  apices;  periapical  region  prob- 
ably  normal. 


Fig.  204. 


Fig.  205. 


Fig.  204. — Lower  left  second  molar,  pulp  vital,  periapical  region  normal.  Third 
molar,  broken-down  roots.  Inferior  dental  canal  is  seen  some  distance  beneath  the 
roots  of  these  teeth. 

Fig.  205. — Lower  left  first  molar  pulpless,  partial  root  fillings,  periapical  thicken- 
ing of  pericementum,  with  some  root  absorption.  Third  molar  partially  erupted;  with 
occlusal   surface  partly  covered   by  bone. 


IlSrTERPKETATION    OF    ROENTGENOGRAMS 


121 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on  Root 
Canal  Treatment 


c. 


Fig.  206. — A.  Ujiper  left  lateral  in- 
cisor, dead  pulp,  with  slight  peridental 
thickening.  B.  Same  tooth  after  open- 
ing, cleansing,  and  sterilizing  of  root 
canal,  showing  diagnostic  wire  in  place, 
extending  to  a|iex.  C.  After  comple- 
tion of  oiieration,  showing  root  iillinf; 
extending  to   apex. 


Fig.  207. — A.  Upper  left  second  pre- 
molar crowned,  part'al  root  lilling,  peri- 
apical area  of  chronic  rarefying  osteitis 
with  granuloma.  B.  Same  tooth,  show- 
ing crown  removed,  and  diagnostic 
wire  in  place  after  opening  and  steriliz- 
ing root  canal.  C.  Treatment  com- 
pleted, showing  lilling  extending  through 
ape.x  into  space  inoduced  by  chronic 
rarefying  osteitis. 


122 


INTERPRETATION    OF    ROENTGENOGRAMS 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on  Root 
Canal  Treatment 


A. 


C. 


■  Fig.  208. — A.  Lower  right  first  molar, 
partial  ^  root  fillings,  sliglit  peridental 
thickening  alioiit  aiiex  of  anterior  root. 
B.  Root  fillings  removed,  canals  steril- 
ized, diagnostic  wires  in  place.  C.  Com- 
pleted operation,  showing  root  canals 
filled  to  apices. 


Fig.  209.—^.  Upper  right  and  left 
central  and  left  central  incisors,  im- 
perfect root  fillings,  periapical  areas  of 
chronic  rarefying  osteitis  with  granu- 
loma. B.  Central  incisors  have  been 
opened,  root  fillings  removed,  and  diag- 
nostic wires  placed  in  position.  Right 
lateral  incisor,  new  root  filling  and 
apical  resection.  C.  Central  incisors, 
after  new  root  fillings  passing  through 
aiiices. 


IISrTERPEETATIOlSr    OF    ROEISTTGElSrOGEAMS 


123 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on  Root 
Canal  Treatment 


Fig.  210.— A.  Upper  right  first  premolar,  partial  root  filling,  periapical  thickening 
due  to  chronic  proliferative  pericementitis.  B.  Same  tooth,  after  opening  and  ster- 
ilization  of   canal,    showing   root   filling   extending   slightly   beyond    apex. 


Fig.  211. — A.  Lower  right  second  premolar,  partial  root  filling,  periapical  area  of 
chronic  rarefying  osteitis  with  granuloma.  B.  Same  tooth,  after  opening  and  ster- 
ilization of  canal,  showing  root  filling  passing  through  apex  into  area  of  destroyed 
bone. 


124 


INTEEPEETATION    OF    KOENTGENOGRAMS 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on  Root 
Canal  Treatment 


c. 

Fig.  212. — A.  Upper  left  second  premolar  pulpless,  partial  root  filling,  periapical 
area  of  chronic  rarefying  osteitis  with  granuloma.  B.  Same  tooth  after  opening  and 
sterilization  of  canal,  with  diagnostic  wires  in  place.  C.  Permanent  root  filling,  pass- 
ing slightly  through  apex. 


Fig.  213. — A.  Upper  left  second  premolar,  showing  two  canals  opened  to  apex 
with  diagnostic  wires  in  place.  No  periapical  abnormality  shown.  B.  Same  tooth 
with   both  canals   completely   filled. 


INTERPEETATION    OF    EOENTGElSrOGRAMS 


125 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on  Root 
Canal  Treatment 


Fig.   214. 


Fig.   215. 


Fig.  216. 

Fig.   214. — Upper   right   lateral   incisor,    root   canal   opened    to    apex,    .sterilized,    and 
diagnostic   wire   in   place. 

Fig.  215. — Upper    left    central    incisor,    root    filled.      Filling    passes    through    apical 
foramen  and  encapsulates  apex. 

Fig.   216. — Lower    right    second   premolar;    double   curve   of   root,    showing   inability 
of  diagnostic  wire  to  negotiate  curve  and  reach  apex;  peridental  thickening  about  apex. 


Fig.  217. — A.  Upper  left  lateral  incisor,  clearly  defined  periapical  area  denoting 
cyst.  B.  Same  case  three  months  after  opening  and  curettement  of  cyst  cavity ;  bone 
legeneration   taking  place. 


126 


INTERPKETATIOlSr    OF    ROENTGElSrOGRAMS 


Illustrating  the  Use  of  the  X-Ray  as  a  Check  on 
Surgical  Treatment 


A. 


B. 


Fig.  218. — A.  Upper  right  premolar 
and  molar  region.  Vital  pulp  in  canine. 
First  premolar  crowned,  apex  projects 
into  large  area  of  chronic  rarefying 
osteitis  with  clearly  defined  border,  due 
to  cyst  formation,  which  apparently  in- 
volves apices  of  canine  and  mesio-buc- 
cal  root  of  first  molar,  though  actually 
these  teeth  are  not  involved.  Second 
premolar  missing.  B.  Six  months  after 
extraction  of  first  premolar  and  curette- 
ment  of  cyst  cavity,  showing  bone  re- 
generation. C.  One  year  after  opera- 
tion, showing  bone  regeneration  almost 
complete. 


C. 

Fig.  219. — A.  Upper  right  second  pre- 
molar, partial  root  filling,  chronic  ab- 
scess with  discharging  sinus.  B.  Taken 
immediately  after  complete  root  filling, 
apical  resection  and  curettement.  C. 
Nine  months  later,  showing  bone  re- 
generation, and  encapsulation  of  root 
end. 


INTERPEETATION    OF    ROEjSTTGEN^OGEAMS 


127 


Views  of  Impacted  Canines,  No  Attempt  at  Localization 


Fig.  220. 


Fig.  221. 


Fig.   222. 


Fig.   223. 


Fig^  224. 


Fig.   225. 


Fig.   224. — Horizontal   position   of    upper   right    impacted    canine. 

Fig.   225. — Unerupted    impacted    upper    first   molar,    lying   in    horizontal    position. 


128 


INTERPEETATIOlSr    OF    ROENTGENOGRAMS 


Localization  of  Impacted  Canine 


A.  B. 

Fig.  226. — Upper  right  impacted  canine.  In  A,  a  more  anterior  view  than  B,  the 
cusp  of  the  canine  overlaps  the  root  of  the  central  to  a  greater  extent  than  it  does  in 
B,  showing  that  the  canine  lies  on  the  lingual   or  palatal  aspect  of  the   other  teeth. 


A. 


Fig.  227. — Upper  left  impacted  canine.  In  A,  a  more  anterior  view  than  B,  the 
cusp  of  the  canine  overlaps  the  root  of  the  central  to  a  greater  extent  than  it  does  in 
B,  showing  that  the  canine  lies  on   the  lingual  or  palatal   as]>ect   of  the   other  teeth. 


INTERPEETATIOX    OF    EOEXTGEXOGEAMS 


129 


Localization  of  Impacted  Canine 


Fig.  228. — Upper  left'  impacted  canine.  In  A,  a  more  anterior  view  than  B.  the 
cusp  of  the  canine  completely  overlaps  the  root  of  the  central  incisor,  while  in  B 
it  only  overlaps  the  root  of  the  lateral,  showing  that  the  c?nine  lies  on  the  lingual 
or  jialatal   aspect   of  the   other  teeth. 


1^^^ 


A.  B. 

Fig.  229. — Upper  left  impacted  canine.  In  A,  a  more  anterior  view  than  B,  the 
cusp  of  the  canine  only  reaches  the  distal  side  of  the  root  of  the  lateral  incisor,  while 
in  B  it  partially  overlaps  the  root  of  this  tooth,  showing  that  the  canine  lies  on  the 
laliial   aspect  of  the   other  teeth.     A  part   of   the  temporary  canine  is  seen  in  B. 


130  INTERPRETATION    OF    ROENTGENOGRAMS 

Horizontal  Impaction  of  Lower  Molars 


Fig.  230. — Horizontal  impaction  of  the  lower  left  third  molar.  Crown  not  cov- 
ered by  bone.  Decay  of  crown  of  second  molar,  shown  by  dark  area.  Upper  third 
molar  unerupted,   and   lying   slightly  to   one   side   of  second   molar. 


Fig.  231. — Horizontal  impaction  of  lower  right  third  molar.  OccUisal  surface  of 
crown  is  tightly  in  apposition  with  posterior  surface  of  crown  and  root  of  second 
molar.  Upper  third  molar  partially  erupted  with  occlusal  surface  of  crown  directed 
backward. 


INTEEPEETATIOX    OF    EOEXTGEXOGRAMS  131 


Fig.   232. — Horizontal    impaction    of   lower   left    third    molar. 


132 


INTERPRETATION    OF    ROENTGENOGRAMS 


Fig.  233. — Horizontal  impaction  of  lower  right  third  molar  with  decaj'  of  crown 
of  second  molar.  Upper  third  molar  unerupted.  The  light  body  shown  above  the 
premolar  teeth   is   an  unerupted   third  molar   on   the   opposite   side. 


Fig.   234. — Oblique    impaction    of    lower    left    third    molar.      Crown    is    largely    covered 

by  bone. 


INTERPRETATION'    OF    EOEXTGEXOGEAMS 


133 


Fig.   235. — Impacted   lower  left   third   molar.      Crown   well   erupted,    and   roots   straight 
and   spread  apart.      Dark  area  in   crown   indicates   caries. 


Fig.   236. — Impacted    uneru]ited    lower    k-tt    tliird    molar.      Roots    only    partially    devel- 
oped.     Uneriipted   upper   third    molar,   apparently   in   good   position. 


134 


IK^TERPRETATIOX    OF    EOENTGEjSTOGEAMS 


Fig.  237. — Impacted  unerupted  lower  premolar  on  left  side.  This  patient  already- 
had  two  premolars  erupted  and  in  good  position  on  the  left  side,  and  three  on  the 
right  side.     In  the  upper  jaw,  the  normal  number  of  teeth  were  present. 


Fig.  238. — Supposedly  edentulous  patient  81  years  of  age.  The  arrow  points  to 
an  unerupted  canine  with  the  crown  directed  forwards.  Above  is  seen  a  film  giving 
a  better  view   of   this   tooth. 


IXTERPEETATIOX    OF    ROEXTGEXOGRA:\rS 


135 


Cysts 


Fig.  239. — Large  area  of  bone  destruction  in  left  angle  and  ramus  of  mandible. 
Sharply  defined  outlines  of  this  area  make  diagnosis  of  cyst  probable.  Patient  gave 
history  of  having  had  abscessed  condition  and  bone  infection  connected  with  third 
molar  and  operation  many  years  before.  At  time  roentgenogram  was  made,  left  side 
.01  face  was  swollen,  there  was  difficulty  in  opening  the  mouth,  ^!id  a  small  sinus  was 
found  on  the  upper  aspect  of  the  gum  at  the  site  of  the  lov/er  third  molar,  through 
which  a  thin  fluid  discharged  into  the  mouth.  A  diagnosis  was  made  of  dental  cyst, 
probably  originating  from  epithelial  remnants  around  the  third  molar,  left  behind  at 
the  first  operation.  At  operation,  the  thin  bone  overlying  the  cavity  was  rongeured 
away  and  the  fluid  contents  and  cyst  wall  removed.  It  was  possible  to  pass  a  probe 
within  the  cavity  almost  up  to  the  mandibular  articulation,  and  down  through  a  per- 
foration into  the  neck.  The  diagnosis  of  cyst  was  confirmed  by  microscopic  examina- 
tion   of   the  tissue   removed,    which   showed   a   condition    similar   to   that    in    Fig.    20. 


Fig.   240. — Roentgenogram  of  same  case  taken   four  months  later,   showing  almost  com- 
plete  obliteration   of   cyst   cavity   by   regeneration   of   bone. 


136  IXTEEPRETATION"    OF    EOEXTGEXOGEAMS 

Cysts 


A.  B. 

Fig.  241. — A.  Cyst  of  right  side  of  upper  jaw,  arising  in  connection  with  small 
piece  of  root  of  first  molar.  The  cyst  extended  upward  encroaching  upon  the  cavity 
of  the  maxillary  sinus,  but  not  communicating  with  it.  B.  Film  showing  more  details 
of  cyst.     Light  area  in  upper  right  corner  is  the  shadow  cast  by   the  malar  bone. 


Osteomyelitis 


Fig.  242. — Right  side,  showing  extensive  bone  destruction  of  lower  jaw  due  to 
acute  osteomyelitis.  The  infection  started  two  weeks  previously  in  connection  with 
the  second  molar.  The  condition  involved  the  lower  jaw  from  angle  to  angle,  all  of 
the  teeth  being  extruded.      (Case  of  Dr.   A.  J.   Kuhnmuench.) 


IXTERPRETATIOX    OF    R(3EXTGEX0GRAMS 


137 


Cysts 


Fig.  243. — Large  area  of  bone  destruction  on  right  side  of  mandible  due  to  cyst 
formation  probably  arising  in  connection  with  irritation  following  periaoical  infec- 
tion about  the   second   premolar  and   first  molar.      Observe   sharp   outline   of  cavity. 


Fig. 


2AA. — Large  infected  cyst  of  right  side   of  mandible  due  to   infection   about   roots 
of   first  molar,   which   bad   been   lost   some   time   previously. 


138  IXTEEPRETATIOX    OF    EOEXTGEXOGEAMS 

Odontomas 


Fig.   245. 


Fig.  246. 


Fig.  245. — Calcified  composite  odontoma  of  right  side  of  mandible  in  an  adult. 
Patient  for  several  years  had  had  several  sinuses  discharging  on  the  skin  at  the  lower 
border  of  the  jaw.  In  the  mouth,  the  teeth  were  absent,  but  pus  discharged  through 
several  sinvises  at  the  bottom  of  which  bard  substance  could  be  felt  with  a  probe. 
X-ray  shows  several  irregular  masses,  denser  than  bone,  in  places  resembling  tooth 
structure. 

Fig.  246. — Calcified  composite  odontoma  of  lower  jaw  resembling  in  history  and 
clinical  signs   the   preceding   case. 


Fig.  247. — Calcified  composite  odontoma  in  a  boy  ten  years  of  age.  Symptoms  be- 
gan with  inflammatory  swelling  of  lower  jaw,  pus  finally  pointing  externally  and 
drained  by  incision  near  angle  of  jaw.  A  diagnosis  of  osteomyelitis  was  made. 
Swelling  and  pus  discharge  were  still  present  when  first  seen  ljy  author  two  weeks 
after  incision.  No  molar  teeth  erupted,  and  no  history  of  ever  being  present.  X-ray 
shows  unerupted  first  molar  near  lower  border  of  jaw.  Behind  and  above  this  is  seen 
a  dense  irregular  mass,  in  places  showing  outlines  of  parts  of  teeth,  extending  well 
back  into  ramus  of  jaw.  Operation  consisted  in  removing  the  mass  and  the  unerupted 
tooth   from   within   the   mouth.     Tumor  weighed   IJ/2    oz. 


IXTERPRETATIOX    OF    ROEXTGEXOGRA.MS 


139 


Fig.  248. — Periapical  bone  destruction  connected  with  lower  left  second  molar. 
Patient,  fourteen  years  of  age,  had  lost  first  molar  on  that  side  some  years  pre- 
viously. For  several  months  had  had  a  sinus  discharging  through  the  skiii  just  be- 
low the  lower  border  of  the  mandible.  The  second  molar  appeared  normal  except 
for  a  large  filling.     On  extraction  of  this  tooth  a  dead  infected   pulp  was  found. 

The  crowns  of  the  unerupted  upper  and  lower  third  molars  with  undeveloped 
roots  are  shown.  Upper  third  molar  of  opposite  side  is  seen  as  a  light  area  above 
the  premolar  region. 


Fig.   249. — Retained    piece    of    root    of    lower    left    first    molar,    which    gave    rise    to 
chronic  sinus  with  purulent  discharge  beneath  jaw,   extending  over  a  period  of  years. 


140 


IXTEEPEETATIOX    OF    EOEXTGEXOGEAMS 


Fig.  250. — Root  of  upper  right  first  molar  lost  in  maxillary  sinus  during  at- 
tempted extraction.  A  plate  should  always  be  made  in  a  case  of  this  kind,  the  two 
sides  of  the  face  being  made  to  overlap  as  much  as  possible,  so  that  the  maxillary 
sinus  will  not  be   obscured  by   the  bone   of  the   opposite  side. 


Fig.   251. — Root    of   upper    right   first    molar   lost    in    maxillary    sinus    during   attempted 

extraction. 


INTERPRETATIOIN'    OF    EOEXTGEXOGrtAMS 


141 


Fig.  252. — Roentgenogram  of  right  side,  showing  lack  of  development  of  both  pre- 
molars and  third  molar  in  upper  jaw  and  second  premolar  and  third  molar  in  lower 
jaw.  Patient  gave  history  of  never  having  erupted  upper  first  and  second  premolars 
and  lower  second  premolar  on  either  side.  Referred  by  Dr.  Carl  B.  Case  for  roent- 
ger.ographic  examination. 


Fig.  253. — Same   case,  showing  similar  condition  on  left  side. 


142  IjSfTEEPEETATIOX    OF    EOEXTGEXOGEAMS 

Fractures 


Fig.  254. — Fracture  of  left  side  of  mandible  just  in  front  of  second  molar.  First 
molar  missing.  The  line  of  fracture  in  this  region  is  nearly  always  oblique,  running 
from  above  downward  and  backward. 


Fig.  255. — Fracture  of  left  side  of  mandible  in  second  premolar  region.  The  root 
of  this  tooth  is  found  in  the  line  of  fracture,  and  will  jircliably  lequire  extraction 
before  union  can   occur. 


IXTEEPRETxVTIOX    OF    EOEXTGEXOGRAMS  143 

Fractures 


> 

> 

^l^^^^Ev 

1 

H^ 

i 

.Jhh 

J 

Fig.   256. — Fracture   of   left   side   of   mandible   near   canine   tooth,    with    very   few   teeth 
present.     This  is   said  to   be  the   commonest  site   for  fracture  to   occur. 


Fig.  257. — Fracture  through  neck  of  condyle  of  mandible.  The  lower  end  of  the 
small  fragment  in  these  cases  is  generally  pulled  forward  by  the  external  pterygoid 
muscle.  The  ramus  of  the  jaw  is  disjilaced  externally  to  the  smaller  fragment,  caus- 
ing the  lower  teeth   to  be   drawn  over  toward  the  affected   side. 


144  i:n'terpretatio:n'  of  roeittgenograms 

Fractures 


Fig.  258. — Double  fracture  of  mandible  in  molar  region  on  each  side.  Attempted 
fixation  by  means  of  Lane's  plates.  The  plates  had  to  be  removed  after  two  weeks 
owing  to  infection   and  nonunion. 


Fig.   259. — Same    case,    showing   swaged    metal   intermaxillary    splint   in   position. 


INDEX 


A 

Abscess,  chronic,  40 

Alveolar  process,  fracture  of,  90 

Anatomic  landmarks,  roentgeno- 
graphic,   26 

Anatomy  in  relation  to  roentgenog- 
raphy,  24 

B 

Bone  regeneration,  109,  126,  135 
C 

Calcification    of    tooth,    incomplete, 

116,  119 
Caries,    dental,    103,    106,    107,   108, 

114,  119    ■ 
Cementum,  erosion  of,  95,  107 
Clinical  examination,  49 
Coronoid  process,  34 
Cyst  formation,  42,  82,  89,  104,  109, 

112,  125,  126,  135,  136,  137 


D 


De1)ris  epitheliaux  paradentaires,  44 
Density,    relative,    of    various    sub- 
stances in  regard  to  x-ray, 
24 


E 


Empyema  of  maxillary  sinus,  58 

Ethmoid  cells,  34 

Examination,  positions  emi^loyed,  5c 

record  of,  52 
Exostosis,  subperiosteal,  118 


Faradic  test,  50 
Film  stereograms,  70 
Films,  identification  of,  60 

illustrating  root   canal   treatment, 

121-125 
lower  front  region,  abnormal,  111, 

112,  113 
lower  front  region,  normal,  110 
lower  left  region,   abnormal,  118, 
no,    120 


Films— Cont  'd 

lower  left  region,  normal,  117,  118 
lower  right  region,  al>normal,  114, 

115,  116 
lower    right   region,    normal,    113, 

114 
position  for  exposure  of,  57 
ujiper    anterior    region,    almormal, 

81-90 
upper  anterior  region,  normal,  79, 

80,  81 
upper  left  region,  abnormal,  102- 

109 
upper  left  region,  normal,  99,  100, 

101 
upper  right  legion,  abnormal,  OS- 
OS 
upper  right  region,  normal,  91,  92, 

93 
Floor  of  nose,  26,  81 
Fracture,  alveolar  process,  90 
mandible,  142-144 
root,  88,  98,  103 

G 

Gingivopericementitis,   47 
Granuloma,  40 

H 

Histopathologv  of  periajiical  lesions, 

38 
Hyoid  bone,  35 
Hypercementosis,  120 


Identification    of    plates    and    films, 

59 
Impacted    canine,    upper,    127,    128, 

129,  134 
Impacted  first  mnlar,  upper,  106,  127 
Impacted  premolar,  lower,   116,  134 
Impacted    third    molar,    lower,    130- 

134 
Impacted  third  molar,  upper,  94,  124 
Interpretation,  77 


Localization,  23 

by  comparison  of  two  films.  74 


145 


146 


INDEX 


Localization — Cout  'd 

of  impacted  canine,  128,  129 
stereoscopic,  67 

M 

Mandibular  canal,  31,  35,  115,  120 
Maxillary  sinus,  2(3 

involvemeut  in  periapical  disease, 

95,  96,  104,  109 
relation  of  roots  of  teeth  to,  91, 

92,  93,  99,  100,  101 
tooth  root  in,  140 
septum  in,  101,  107 
Mental  foramen,  31,  35,  113,  118 


X 


Xasal  fossa,  26,  81 
O 

Odontogram,  definition  of,  IS 

knowledge  necessary  for  interpre- 
tation of,  19 

Odontoma,  calcified,   138 

Osteitis,  chronic  rarefying,  arseni- 
cal, 90 
with  granuloma,  82,  83,  81,  85, 
86,  87,  88,  95,  96,  97,  98, 
102,  103,  104,  106,  107,  108, 
111,  112,  113,  114,  lis 
with  suppuration,  81,  84.  So,  87, 
S9,  94,  95,  96,  107,  109,  111, 
114,  115,  119,  120,  139. 

Osteomyelitis,   acute,   136 

Osteopericementitis,  47 


Palatine  canal,  posterior,  31 
Palatine  fossa,  anterior,  30,  79 
Pathology,     in     relation     to     dental 

roentgenology,  36 
Perforation  of  root,  86,  87,  102,  105, 

108,  118 
Periapical   dental  lesions,  pathology 

of,  37 
Periapical  disease,  stages,  38,  45 
Pericementitis,   chronic    suppurative, 

46,  88,  102,  104,  105,  106, 

112,  113,  116 
periapical,  chronic,  84.  85,  87,  88, 

93,  94,  102,  103,  104,  112, 

115,  116,  118,  120 


Peridental  line,  25,  79,  100 

Peridental  thickening,  40 

Plate  rest,  56 

Plate  stereograms,  68 

Plates,  identification  of,  59 
position  for  exposure  of,  56 
roentgenographic  landmarks  in,  33 
use  of,  51 

Prognosis  as  aided  bv  roentgen  rav, 
62 

Pulp,  test  for  vitalitv  of,  50 

Pyorrhea  alveolaris,  *46,  65,  88,  102, 
104,  105,  106,  112,  113,  116 

R 

Rarefying  osteitis,  chronic,  45 

Record  of  examination,  52 

Resection  of  root,  122,  126 

Roentgenogram,  18 

Roentgenograms,  interpretation  of, 
77 

Roentgenographic  findings  in  rela- 
tion to  prognosis  and  treat- 
ment, 62 

Roentgenography,  limitations  of,  20 

Roeirtgenologic  examination,  posi- 
tions used,  53 

Root,  fracture  of,  88,  98,  103 

perforation   of,   86,    87,   102,   105, 
108,  118 

Routine  examination,  49 

S 

Sinuses,  j^osition  for  examination  of, 

57 
Stereogram,  18 
Stereograms,  mounting,   72 
Stereoroentgenography,  67 
Stereoscopic  localization,  67 
Streptococcus,  38 
Supernumerary  tooth,  90,  134 
Suppurative   pericementitis,   clironic, 

65.   88.   102.   3  04,   105,  106, 

112,  113    116 


T 


Teeth,  absence  of.  141 

anatomic    relations    to    maxillary 
sinus,  26 
Terms,  explanation  of,  18 
Tootli,  supernumerary,  90,  134 
Treatment,  bearing  of  x-ray  examin- 
ation on,  63 


JO  AJadoij 


RK270 


